Okay - for the engineers and scientists on the list.
I was thinking about this question -
Its clear that it takes more energy (and greater force) to accelerate a heavier body than a smaller one. Also to stop heavier body already in motion.  Does anyone know if the relationship of force required to the mass is linear or exponential?  Or - putting it another way as players get heavier does the force required at the margin go up ?
Jon



_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe.

Okay - for the engineers and scientists on the list.
I was thinking about this question -
Its clear that it takes more energy (and greater force) to accelerate a heavier body than a smaller one. Also to stop heavier body already in motion.  Does anyone know if the relationship of force required to the mass is linear or exponential?  Or - putting it another way as players get heavier does the force required at the margin go up ?
Jon



_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. For the same acceleration, the force is proportional to the mass. f=ma is a basic foundation of first-semester physics.

-- Carl
.
----- Original Message -----
From: Jonathan Jeffer
To: Judo-L Judo-L
Sent: Monday, April 19, 2010 6:47 PM
Subject: [JudoList] judo physics **** question


Okay - for the engineers and scientists on the list.
I was thinking about this question -
Its clear that it takes more energy (and greater force) to accelerate a heavier body than a smaller one. Also to stop heavier body already in motion. Does anyone know if the relationship of force required to the mass is linear or exponential? Or - putting it another way as players get heavier does the force required at the margin go up ?
Jon



_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe.

Okay - for the engineers and scientists on the list.
I was thinking about this question -
Its clear that it takes more energy (and greater force) to accelerate a heavier body than a smaller one. Also to stop heavier body already in motion.  Does anyone know if the relationship of force required to the mass is linear or exponential?  Or - putting it another way as players get heavier does the force required at the margin go up ?
Jon



_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. For the same acceleration, the force is proportional to the mass. f=ma is a basic foundation of first-semester physics.

-- Carl
.
----- Original Message -----
From: Jonathan Jeffer
To: Judo-L Judo-L
Sent: Monday, April 19, 2010 6:47 PM
Subject: [JudoList] judo physics **** question


Okay - for the engineers and scientists on the list.
I was thinking about this question -
Its clear that it takes more energy (and greater force) to accelerate a heavier body than a smaller one. Also to stop heavier body already in motion. Does anyone know if the relationship of force required to the mass is linear or exponential? Or - putting it another way as players get heavier does the force required at the margin go up ?
Jon



_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. 1st semester was a long time ago. I know the equation I was just not thinking clearly.  Makes sense.


Subject: Re: [JudoList] judo physics **** question
Date: Monday, April 19, 2010, 6:51 PM

For the same acceleration, the force is proportional to the mass.  f=ma is a basic foundation of first-semester physics.

  -- Carl
.
  ----- Original Message -----
  From: Jonathan Jeffer
  To: Judo-L Judo-L
  Sent: Monday, April 19, 2010 6:47 PM
  Subject: [JudoList] judo physics **** question


  Okay - for the engineers and scientists on the list.
  I was thinking about this question -
  Its clear that it takes more energy (and greater force) to accelerate a heavier body than a smaller one. Also to stop heavier body already in motion. Does anyone know if the relationship of force required to the mass is linear or exponential? Or - putting it another way as players get heavier does the force required at the margin go up ?
  Jon


       
  _______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe.

Okay - for the engineers and scientists on the list.
I was thinking about this question -
Its clear that it takes more energy (and greater force) to accelerate a heavier body than a smaller one. Also to stop heavier body already in motion.  Does anyone know if the relationship of force required to the mass is linear or exponential?  Or - putting it another way as players get heavier does the force required at the margin go up ?
Jon



_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. For the same acceleration, the force is proportional to the mass. f=ma is a basic foundation of first-semester physics.

-- Carl
.
----- Original Message -----
From: Jonathan Jeffer
To: Judo-L Judo-L
Sent: Monday, April 19, 2010 6:47 PM
Subject: [JudoList] judo physics **** question


Okay - for the engineers and scientists on the list.
I was thinking about this question -
Its clear that it takes more energy (and greater force) to accelerate a heavier body than a smaller one. Also to stop heavier body already in motion. Does anyone know if the relationship of force required to the mass is linear or exponential? Or - putting it another way as players get heavier does the force required at the margin go up ?
Jon



_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. 1st semester was a long time ago. I know the equation I was just not thinking clearly.  Makes sense.


Subject: Re: [JudoList] judo physics **** question
Date: Monday, April 19, 2010, 6:51 PM

For the same acceleration, the force is proportional to the mass.  f=ma is a basic foundation of first-semester physics.

  -- Carl
.
  ----- Original Message -----
  From: Jonathan Jeffer
  To: Judo-L Judo-L
  Sent: Monday, April 19, 2010 6:47 PM
  Subject: [JudoList] judo physics **** question


  Okay - for the engineers and scientists on the list.
  I was thinking about this question -
  Its clear that it takes more energy (and greater force) to accelerate a heavier body than a smaller one. Also to stop heavier body already in motion. Does anyone know if the relationship of force required to the mass is linear or exponential? Or - putting it another way as players get heavier does the force required at the margin go up ?
  Jon


       
  _______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. I am not going to forward this to my dojo. I have nothing but engineers.
Including 2 MIT PhD's try to teach this group of people an art. I have said,
"throw to the perpendicular of the line that connects to the back of your
feet" so many times I get light headed every time I go to class. I even
started teaching throws as equations. aaaaaaaaaaaaaaHHHHHHHHHHHHHHHH

Richard Porro

If it isn't full contact, it isn't martial arts!
-----Original Message-----
From: judolist- [mailto:judolist-] On
Behalf Of Jonathan Jeffer
Sent: Monday, April 19, 2010 5:47 PM
To: Judo-L Judo-L
Subject: [JudoList] judo physics **** question

Okay - for the engineers and scientists on the list.
I was thinking about this question -
Its clear that it takes more energy (and greater force) to accelerate a
heavier body than a smaller one. Also to stop heavier body already in
motion.  Does anyone know if the relationship of force required to the mass
is linear or exponential?  Or - putting it another way as players get
heavier does the force required at the margin go up ?
Jon



_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe.

Okay - for the engineers and scientists on the list.
I was thinking about this question -
Its clear that it takes more energy (and greater force) to accelerate a heavier body than a smaller one. Also to stop heavier body already in motion.  Does anyone know if the relationship of force required to the mass is linear or exponential?  Or - putting it another way as players get heavier does the force required at the margin go up ?
Jon



_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. For the same acceleration, the force is proportional to the mass. f=ma is a basic foundation of first-semester physics.

-- Carl
.
----- Original Message -----
From: Jonathan Jeffer
To: Judo-L Judo-L
Sent: Monday, April 19, 2010 6:47 PM
Subject: [JudoList] judo physics **** question


Okay - for the engineers and scientists on the list.
I was thinking about this question -
Its clear that it takes more energy (and greater force) to accelerate a heavier body than a smaller one. Also to stop heavier body already in motion. Does anyone know if the relationship of force required to the mass is linear or exponential? Or - putting it another way as players get heavier does the force required at the margin go up ?
Jon



_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. 1st semester was a long time ago. I know the equation I was just not thinking clearly.  Makes sense.


Subject: Re: [JudoList] judo physics **** question
Date: Monday, April 19, 2010, 6:51 PM

For the same acceleration, the force is proportional to the mass.  f=ma is a basic foundation of first-semester physics.

  -- Carl
.
  ----- Original Message -----
  From: Jonathan Jeffer
  To: Judo-L Judo-L
  Sent: Monday, April 19, 2010 6:47 PM
  Subject: [JudoList] judo physics **** question


  Okay - for the engineers and scientists on the list.
  I was thinking about this question -
  Its clear that it takes more energy (and greater force) to accelerate a heavier body than a smaller one. Also to stop heavier body already in motion. Does anyone know if the relationship of force required to the mass is linear or exponential? Or - putting it another way as players get heavier does the force required at the margin go up ?
  Jon


       
  _______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. I am not going to forward this to my dojo. I have nothing but engineers.
Including 2 MIT PhD's try to teach this group of people an art. I have said,
"throw to the perpendicular of the line that connects to the back of your
feet" so many times I get light headed every time I go to class. I even
started teaching throws as equations. aaaaaaaaaaaaaaHHHHHHHHHHHHHHHH

Richard Porro

If it isn't full contact, it isn't martial arts!
-----Original Message-----
From: judolist- [mailto:judolist-] On
Behalf Of Jonathan Jeffer
Sent: Monday, April 19, 2010 5:47 PM
To: Judo-L Judo-L
Subject: [JudoList] judo physics **** question

Okay - for the engineers and scientists on the list.
I was thinking about this question -
Its clear that it takes more energy (and greater force) to accelerate a
heavier body than a smaller one. Also to stop heavier body already in
motion.  Does anyone know if the relationship of force required to the mass
is linear or exponential?  Or - putting it another way as players get
heavier does the force required at the margin go up ?
Jon



_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. Sounds like Monday night class again.:)

Richard Porro

If it isn't full contact, it isn't martial arts!

-----Original Message-----
From: judolist- [mailto:judolist-] On
Behalf Of Carl Hayes
Sent: Monday, April 19, 2010 5:52 PM
To: Discussion of All Aspects of Traditional and Modern Judo
Subject: Re: [JudoList] judo physics **** question

For the same acceleration, the force is proportional to the mass. f=ma is a
basic foundation of first-semester physics.

-- Carl
.
----- Original Message -----
From: Jonathan Jeffer
To: Judo-L Judo-L
Sent: Monday, April 19, 2010 6:47 PM
Subject: [JudoList] judo physics **** question


Okay - for the engineers and scientists on the list.
I was thinking about this question -
Its clear that it takes more energy (and greater force) to accelerate a
heavier body than a smaller one. Also to stop heavier body already in
motion. Does anyone know if the relationship of force required to the mass
is linear or exponential? Or - putting it another way as players get heavier
does the force required at the margin go up ?
Jon



_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe.

Okay - for the engineers and scientists on the list.
I was thinking about this question -
Its clear that it takes more energy (and greater force) to accelerate a heavier body than a smaller one. Also to stop heavier body already in motion.  Does anyone know if the relationship of force required to the mass is linear or exponential?  Or - putting it another way as players get heavier does the force required at the margin go up ?
Jon



_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. For the same acceleration, the force is proportional to the mass. f=ma is a basic foundation of first-semester physics.

-- Carl
.
----- Original Message -----
From: Jonathan Jeffer
To: Judo-L Judo-L
Sent: Monday, April 19, 2010 6:47 PM
Subject: [JudoList] judo physics **** question


Okay - for the engineers and scientists on the list.
I was thinking about this question -
Its clear that it takes more energy (and greater force) to accelerate a heavier body than a smaller one. Also to stop heavier body already in motion. Does anyone know if the relationship of force required to the mass is linear or exponential? Or - putting it another way as players get heavier does the force required at the margin go up ?
Jon



_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. 1st semester was a long time ago. I know the equation I was just not thinking clearly.  Makes sense.


Subject: Re: [JudoList] judo physics **** question
Date: Monday, April 19, 2010, 6:51 PM

For the same acceleration, the force is proportional to the mass.  f=ma is a basic foundation of first-semester physics.

  -- Carl
.
  ----- Original Message -----
  From: Jonathan Jeffer
  To: Judo-L Judo-L
  Sent: Monday, April 19, 2010 6:47 PM
  Subject: [JudoList] judo physics **** question


  Okay - for the engineers and scientists on the list.
  I was thinking about this question -
  Its clear that it takes more energy (and greater force) to accelerate a heavier body than a smaller one. Also to stop heavier body already in motion. Does anyone know if the relationship of force required to the mass is linear or exponential? Or - putting it another way as players get heavier does the force required at the margin go up ?
  Jon


       
  _______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. I am not going to forward this to my dojo. I have nothing but engineers.
Including 2 MIT PhD's try to teach this group of people an art. I have said,
"throw to the perpendicular of the line that connects to the back of your
feet" so many times I get light headed every time I go to class. I even
started teaching throws as equations. aaaaaaaaaaaaaaHHHHHHHHHHHHHHHH

Richard Porro

If it isn't full contact, it isn't martial arts!
-----Original Message-----
From: judolist- [mailto:judolist-] On
Behalf Of Jonathan Jeffer
Sent: Monday, April 19, 2010 5:47 PM
To: Judo-L Judo-L
Subject: [JudoList] judo physics **** question

Okay - for the engineers and scientists on the list.
I was thinking about this question -
Its clear that it takes more energy (and greater force) to accelerate a
heavier body than a smaller one. Also to stop heavier body already in
motion.  Does anyone know if the relationship of force required to the mass
is linear or exponential?  Or - putting it another way as players get
heavier does the force required at the margin go up ?
Jon



_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. Sounds like Monday night class again.:)

Richard Porro

If it isn't full contact, it isn't martial arts!

-----Original Message-----
From: judolist- [mailto:judolist-] On
Behalf Of Carl Hayes
Sent: Monday, April 19, 2010 5:52 PM
To: Discussion of All Aspects of Traditional and Modern Judo
Subject: Re: [JudoList] judo physics **** question

For the same acceleration, the force is proportional to the mass. f=ma is a
basic foundation of first-semester physics.

-- Carl
.
----- Original Message -----
From: Jonathan Jeffer
To: Judo-L Judo-L
Sent: Monday, April 19, 2010 6:47 PM
Subject: [JudoList] judo physics **** question


Okay - for the engineers and scientists on the list.
I was thinking about this question -
Its clear that it takes more energy (and greater force) to accelerate a
heavier body than a smaller one. Also to stop heavier body already in
motion. Does anyone know if the relationship of force required to the mass
is linear or exponential? Or - putting it another way as players get heavier
does the force required at the margin go up ?
Jon



_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. What I was wondering about is something I have observed - that big people tend to accelerate slower and change direction slower  than smaller people.
The energy needed to accelerate more mass is clear.  What I was wonder about was whether it gets harder as mass goes up.  What Carl corrected me on is that its not actually harder, because the relationship is linear.  Other factors might not be linear.  Like the ratio of strength to mass.

--- On Tue, 4/20/10, Richard Porro <> wrote:

From: Richard Porro <>
Subject: Re: [JudoList] judo physics **** question
To: "'Discussion of All Aspects of Traditional and Modern Judo'" <>
Date: Tuesday, April 20, 2010, 11:19 AM

I am not going to forward this to my dojo. I have nothing but engineers.
Including 2 MIT PhD's try to teach this group of people an art. I have said,
"throw to the perpendicular of the line that connects to the back of your
feet" so many times I get light headed every time I go to class. I even
started teaching throws as equations. aaaaaaaaaaaaaaHHHHHHHHHHHHHHHH

Richard Porro

If it isn't full contact, it isn't martial arts!
-----Original Message-----
From: judolist- [mailto:judolist-] On
Behalf Of Jonathan Jeffer
Sent: Monday, April 19, 2010 5:47 PM
To: Judo-L Judo-L
Subject: [JudoList] judo physics **** question

Okay - for the engineers and scientists on the list.
I was thinking about this question -
Its clear that it takes more energy (and greater force) to accelerate a
heavier body than a smaller one. Also to stop heavier body already in
motion.  Does anyone know if the relationship of force required to the mass
is linear or exponential?  Or - putting it another way as players get
heavier does the force required at the margin go up ?
Jon


     
_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe.

Okay - for the engineers and scientists on the list.
I was thinking about this question -
Its clear that it takes more energy (and greater force) to accelerate a heavier body than a smaller one. Also to stop heavier body already in motion.  Does anyone know if the relationship of force required to the mass is linear or exponential?  Or - putting it another way as players get heavier does the force required at the margin go up ?
Jon



_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. For the same acceleration, the force is proportional to the mass. f=ma is a basic foundation of first-semester physics.

-- Carl
.
----- Original Message -----
From: Jonathan Jeffer
To: Judo-L Judo-L
Sent: Monday, April 19, 2010 6:47 PM
Subject: [JudoList] judo physics **** question


Okay - for the engineers and scientists on the list.
I was thinking about this question -
Its clear that it takes more energy (and greater force) to accelerate a heavier body than a smaller one. Also to stop heavier body already in motion. Does anyone know if the relationship of force required to the mass is linear or exponential? Or - putting it another way as players get heavier does the force required at the margin go up ?
Jon



_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. 1st semester was a long time ago. I know the equation I was just not thinking clearly.  Makes sense.


Subject: Re: [JudoList] judo physics **** question
Date: Monday, April 19, 2010, 6:51 PM

For the same acceleration, the force is proportional to the mass.  f=ma is a basic foundation of first-semester physics.

  -- Carl
.
  ----- Original Message -----
  From: Jonathan Jeffer
  To: Judo-L Judo-L
  Sent: Monday, April 19, 2010 6:47 PM
  Subject: [JudoList] judo physics **** question


  Okay - for the engineers and scientists on the list.
  I was thinking about this question -
  Its clear that it takes more energy (and greater force) to accelerate a heavier body than a smaller one. Also to stop heavier body already in motion. Does anyone know if the relationship of force required to the mass is linear or exponential? Or - putting it another way as players get heavier does the force required at the margin go up ?
  Jon


       
  _______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. I am not going to forward this to my dojo. I have nothing but engineers.
Including 2 MIT PhD's try to teach this group of people an art. I have said,
"throw to the perpendicular of the line that connects to the back of your
feet" so many times I get light headed every time I go to class. I even
started teaching throws as equations. aaaaaaaaaaaaaaHHHHHHHHHHHHHHHH

Richard Porro

If it isn't full contact, it isn't martial arts!
-----Original Message-----
From: judolist- [mailto:judolist-] On
Behalf Of Jonathan Jeffer
Sent: Monday, April 19, 2010 5:47 PM
To: Judo-L Judo-L
Subject: [JudoList] judo physics **** question

Okay - for the engineers and scientists on the list.
I was thinking about this question -
Its clear that it takes more energy (and greater force) to accelerate a
heavier body than a smaller one. Also to stop heavier body already in
motion.  Does anyone know if the relationship of force required to the mass
is linear or exponential?  Or - putting it another way as players get
heavier does the force required at the margin go up ?
Jon



_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. Sounds like Monday night class again.:)

Richard Porro

If it isn't full contact, it isn't martial arts!

-----Original Message-----
From: judolist- [mailto:judolist-] On
Behalf Of Carl Hayes
Sent: Monday, April 19, 2010 5:52 PM
To: Discussion of All Aspects of Traditional and Modern Judo
Subject: Re: [JudoList] judo physics **** question

For the same acceleration, the force is proportional to the mass. f=ma is a
basic foundation of first-semester physics.

-- Carl
.
----- Original Message -----
From: Jonathan Jeffer
To: Judo-L Judo-L
Sent: Monday, April 19, 2010 6:47 PM
Subject: [JudoList] judo physics **** question


Okay - for the engineers and scientists on the list.
I was thinking about this question -
Its clear that it takes more energy (and greater force) to accelerate a
heavier body than a smaller one. Also to stop heavier body already in
motion. Does anyone know if the relationship of force required to the mass
is linear or exponential? Or - putting it another way as players get heavier
does the force required at the margin go up ?
Jon



_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. What I was wondering about is something I have observed - that big people tend to accelerate slower and change direction slower  than smaller people.
The energy needed to accelerate more mass is clear.  What I was wonder about was whether it gets harder as mass goes up.  What Carl corrected me on is that its not actually harder, because the relationship is linear.  Other factors might not be linear.  Like the ratio of strength to mass.

--- On Tue, 4/20/10, Richard Porro <> wrote:

From: Richard Porro <>
Subject: Re: [JudoList] judo physics **** question
To: "'Discussion of All Aspects of Traditional and Modern Judo'" <>
Date: Tuesday, April 20, 2010, 11:19 AM

I am not going to forward this to my dojo. I have nothing but engineers.
Including 2 MIT PhD's try to teach this group of people an art. I have said,
"throw to the perpendicular of the line that connects to the back of your
feet" so many times I get light headed every time I go to class. I even
started teaching throws as equations. aaaaaaaaaaaaaaHHHHHHHHHHHHHHHH

Richard Porro

If it isn't full contact, it isn't martial arts!
-----Original Message-----
From: judolist- [mailto:judolist-] On
Behalf Of Jonathan Jeffer
Sent: Monday, April 19, 2010 5:47 PM
To: Judo-L Judo-L
Subject: [JudoList] judo physics **** question

Okay - for the engineers and scientists on the list.
I was thinking about this question -
Its clear that it takes more energy (and greater force) to accelerate a
heavier body than a smaller one. Also to stop heavier body already in
motion.  Does anyone know if the relationship of force required to the mass
is linear or exponential?  Or - putting it another way as players get
heavier does the force required at the margin go up ?
Jon


     
_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. You are correct. It takes longer for a larger person to arrive at the "sweet" spot of no return as my sensei used to say. Most people try to throw to soon and therefore have to force the engagement.


T Ryan





-----Original Message-----
From: Jonathan Jeffer <>
To: Discussion of All Aspects of Traditional and Modern Judo <>
Sent: Tue, Apr 20, 2010 12:10 pm
Subject: Re: [JudoList] judo physics **** question


What I was wondering about is something I have observed - that big people tend
to accelerate slower and change direction slower than smaller people.
The energy needed to accelerate more mass is clear. What I was wonder about was
whether it gets harder as mass goes up. What Carl corrected me on is that its
not actually harder, because the relationship is linear. Other factors might
not be linear. Like the ratio of strength to mass.

--- On Tue, 4/20/10, Richard Porro <> wrote:

From: Richard Porro <>
Subject: Re: [JudoList] judo physics **** question
To: "'Discussion of All Aspects of Traditional and Modern Judo'"
<>
Date: Tuesday, April 20, 2010, 11:19 AM

I am not going to forward this to my dojo. I have nothing but engineers.
Including 2 MIT PhD's try to teach this group of people an art. I have said,
"throw to the perpendicular of the line that connects to the back of your
feet" so many times I get light headed every time I go to class. I even
started teaching throws as equations. aaaaaaaaaaaaaaHHHHHHHHHHHHHHHH

Richard Porro

If it isn't full contact, it isn't martial arts!
-----Original Message-----
From: judolist- [mailto:judolist-] On
Behalf Of Jonathan Jeffer
Sent: Monday, April 19, 2010 5:47 PM
To: Judo-L Judo-L
Subject: [JudoList] judo physics **** question

Okay - for the engineers and scientists on the list.
I was thinking about this question -
Its clear that it takes more energy (and greater force) to accelerate a
heavier body than a smaller one. Also to stop heavier body already in
motion. Does anyone know if the relationship of force required to the mass
is linear or exponential? Or - putting it another way as players get
heavier does the force required at the margin go up ?
Jon



_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe.

Okay - for the engineers and scientists on the list.
I was thinking about this question -
Its clear that it takes more energy (and greater force) to accelerate a heavier body than a smaller one. Also to stop heavier body already in motion.  Does anyone know if the relationship of force required to the mass is linear or exponential?  Or - putting it another way as players get heavier does the force required at the margin go up ?
Jon



_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. For the same acceleration, the force is proportional to the mass. f=ma is a basic foundation of first-semester physics.

-- Carl
.
----- Original Message -----
From: Jonathan Jeffer
To: Judo-L Judo-L
Sent: Monday, April 19, 2010 6:47 PM
Subject: [JudoList] judo physics **** question


Okay - for the engineers and scientists on the list.
I was thinking about this question -
Its clear that it takes more energy (and greater force) to accelerate a heavier body than a smaller one. Also to stop heavier body already in motion. Does anyone know if the relationship of force required to the mass is linear or exponential? Or - putting it another way as players get heavier does the force required at the margin go up ?
Jon



_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. 1st semester was a long time ago. I know the equation I was just not thinking clearly.  Makes sense.


Subject: Re: [JudoList] judo physics **** question
Date: Monday, April 19, 2010, 6:51 PM

For the same acceleration, the force is proportional to the mass.  f=ma is a basic foundation of first-semester physics.

  -- Carl
.
  ----- Original Message -----
  From: Jonathan Jeffer
  To: Judo-L Judo-L
  Sent: Monday, April 19, 2010 6:47 PM
  Subject: [JudoList] judo physics **** question


  Okay - for the engineers and scientists on the list.
  I was thinking about this question -
  Its clear that it takes more energy (and greater force) to accelerate a heavier body than a smaller one. Also to stop heavier body already in motion. Does anyone know if the relationship of force required to the mass is linear or exponential? Or - putting it another way as players get heavier does the force required at the margin go up ?
  Jon


       
  _______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. I am not going to forward this to my dojo. I have nothing but engineers.
Including 2 MIT PhD's try to teach this group of people an art. I have said,
"throw to the perpendicular of the line that connects to the back of your
feet" so many times I get light headed every time I go to class. I even
started teaching throws as equations. aaaaaaaaaaaaaaHHHHHHHHHHHHHHHH

Richard Porro

If it isn't full contact, it isn't martial arts!
-----Original Message-----
From: judolist- [mailto:judolist-] On
Behalf Of Jonathan Jeffer
Sent: Monday, April 19, 2010 5:47 PM
To: Judo-L Judo-L
Subject: [JudoList] judo physics **** question

Okay - for the engineers and scientists on the list.
I was thinking about this question -
Its clear that it takes more energy (and greater force) to accelerate a
heavier body than a smaller one. Also to stop heavier body already in
motion.  Does anyone know if the relationship of force required to the mass
is linear or exponential?  Or - putting it another way as players get
heavier does the force required at the margin go up ?
Jon



_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. Sounds like Monday night class again.:)

Richard Porro

If it isn't full contact, it isn't martial arts!

-----Original Message-----
From: judolist- [mailto:judolist-] On
Behalf Of Carl Hayes
Sent: Monday, April 19, 2010 5:52 PM
To: Discussion of All Aspects of Traditional and Modern Judo
Subject: Re: [JudoList] judo physics **** question

For the same acceleration, the force is proportional to the mass. f=ma is a
basic foundation of first-semester physics.

-- Carl
.
----- Original Message -----
From: Jonathan Jeffer
To: Judo-L Judo-L
Sent: Monday, April 19, 2010 6:47 PM
Subject: [JudoList] judo physics **** question


Okay - for the engineers and scientists on the list.
I was thinking about this question -
Its clear that it takes more energy (and greater force) to accelerate a
heavier body than a smaller one. Also to stop heavier body already in
motion. Does anyone know if the relationship of force required to the mass
is linear or exponential? Or - putting it another way as players get heavier
does the force required at the margin go up ?
Jon



_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. What I was wondering about is something I have observed - that big people tend to accelerate slower and change direction slower  than smaller people.
The energy needed to accelerate more mass is clear.  What I was wonder about was whether it gets harder as mass goes up.  What Carl corrected me on is that its not actually harder, because the relationship is linear.  Other factors might not be linear.  Like the ratio of strength to mass.

--- On Tue, 4/20/10, Richard Porro <> wrote:

From: Richard Porro <>
Subject: Re: [JudoList] judo physics **** question
To: "'Discussion of All Aspects of Traditional and Modern Judo'" <>
Date: Tuesday, April 20, 2010, 11:19 AM

I am not going to forward this to my dojo. I have nothing but engineers.
Including 2 MIT PhD's try to teach this group of people an art. I have said,
"throw to the perpendicular of the line that connects to the back of your
feet" so many times I get light headed every time I go to class. I even
started teaching throws as equations. aaaaaaaaaaaaaaHHHHHHHHHHHHHHHH

Richard Porro

If it isn't full contact, it isn't martial arts!
-----Original Message-----
From: judolist- [mailto:judolist-] On
Behalf Of Jonathan Jeffer
Sent: Monday, April 19, 2010 5:47 PM
To: Judo-L Judo-L
Subject: [JudoList] judo physics **** question

Okay - for the engineers and scientists on the list.
I was thinking about this question -
Its clear that it takes more energy (and greater force) to accelerate a
heavier body than a smaller one. Also to stop heavier body already in
motion.  Does anyone know if the relationship of force required to the mass
is linear or exponential?  Or - putting it another way as players get
heavier does the force required at the margin go up ?
Jon


     
_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. You are correct. It takes longer for a larger person to arrive at the "sweet" spot of no return as my sensei used to say. Most people try to throw to soon and therefore have to force the engagement.


T Ryan





-----Original Message-----
From: Jonathan Jeffer <>
To: Discussion of All Aspects of Traditional and Modern Judo <>
Sent: Tue, Apr 20, 2010 12:10 pm
Subject: Re: [JudoList] judo physics **** question


What I was wondering about is something I have observed - that big people tend
to accelerate slower and change direction slower than smaller people.
The energy needed to accelerate more mass is clear. What I was wonder about was
whether it gets harder as mass goes up. What Carl corrected me on is that its
not actually harder, because the relationship is linear. Other factors might
not be linear. Like the ratio of strength to mass.

--- On Tue, 4/20/10, Richard Porro <> wrote:

From: Richard Porro <>
Subject: Re: [JudoList] judo physics **** question
To: "'Discussion of All Aspects of Traditional and Modern Judo'"
<>
Date: Tuesday, April 20, 2010, 11:19 AM

I am not going to forward this to my dojo. I have nothing but engineers.
Including 2 MIT PhD's try to teach this group of people an art. I have said,
"throw to the perpendicular of the line that connects to the back of your
feet" so many times I get light headed every time I go to class. I even
started teaching throws as equations. aaaaaaaaaaaaaaHHHHHHHHHHHHHHHH

Richard Porro

If it isn't full contact, it isn't martial arts!
-----Original Message-----
From: judolist- [mailto:judolist-] On
Behalf Of Jonathan Jeffer
Sent: Monday, April 19, 2010 5:47 PM
To: Judo-L Judo-L
Subject: [JudoList] judo physics **** question

Okay - for the engineers and scientists on the list.
I was thinking about this question -
Its clear that it takes more energy (and greater force) to accelerate a
heavier body than a smaller one. Also to stop heavier body already in
motion. Does anyone know if the relationship of force required to the mass
is linear or exponential? Or - putting it another way as players get
heavier does the force required at the margin go up ?
Jon



_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. Do they really accelerate slower? Or do they just have a greater distance to travel? But maybe they really do accelerate slower, because after all their mass is proportional to the cube of their height if they are of similar build -- very nonlinear.

So, for example, if you are 10% taller than I am (and built the same), you must move 10% farther, and you must move 33% more mass, too. So you'd better be 44% stronger if you want to move a body length in the same time I move a body length.

Yeah, I'll bet they accelerate slower.

-- Carl
.
----- Original Message -----
From: Jonathan Jeffer
To: Discussion of All Aspects of Traditional and Modern Judo
Sent: Tuesday, April 20, 2010 12:10 PM
Subject: Re: [JudoList] judo physics **** question


What I was wondering about is something I have observed - that big people tend to accelerate slower and change direction slower than smaller people.
The energy needed to accelerate more mass is clear. What I was wonder about was whether it gets harder as mass goes up. What Carl corrected me on is that its not actually harder, because the relationship is linear. Other factors might not be linear. Like the ratio of strength to mass.

--- On Tue, 4/20/10, Richard Porro <> wrote:

From: Richard Porro <>
Subject: Re: [JudoList] judo physics **** question
To: "'Discussion of All Aspects of Traditional and Modern Judo'" <>
Date: Tuesday, April 20, 2010, 11:19 AM

I am not going to forward this to my dojo. I have nothing but engineers.
Including 2 MIT PhD's try to teach this group of people an art. I have said,
"throw to the perpendicular of the line that connects to the back of your
feet" so many times I get light headed every time I go to class. I even
started teaching throws as equations. aaaaaaaaaaaaaaHHHHHHHHHHHHHHHH

Richard Porro

If it isn't full contact, it isn't martial arts!
-----Original Message-----
From: judolist- [mailto:judolist-] On
Behalf Of Jonathan Jeffer
Sent: Monday, April 19, 2010 5:47 PM
To: Judo-L Judo-L
Subject: [JudoList] judo physics **** question

Okay - for the engineers and scientists on the list.
I was thinking about this question -
Its clear that it takes more energy (and greater force) to accelerate a
heavier body than a smaller one. Also to stop heavier body already in
motion. Does anyone know if the relationship of force required to the mass
is linear or exponential? Or - putting it another way as players get
heavier does the force required at the margin go up ?
Jon



_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe.

Okay - for the engineers and scientists on the list.
I was thinking about this question -
Its clear that it takes more energy (and greater force) to accelerate a heavier body than a smaller one. Also to stop heavier body already in motion.  Does anyone know if the relationship of force required to the mass is linear or exponential?  Or - putting it another way as players get heavier does the force required at the margin go up ?
Jon



_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. For the same acceleration, the force is proportional to the mass. f=ma is a basic foundation of first-semester physics.

-- Carl
.
----- Original Message -----
From: Jonathan Jeffer
To: Judo-L Judo-L
Sent: Monday, April 19, 2010 6:47 PM
Subject: [JudoList] judo physics **** question


Okay - for the engineers and scientists on the list.
I was thinking about this question -
Its clear that it takes more energy (and greater force) to accelerate a heavier body than a smaller one. Also to stop heavier body already in motion. Does anyone know if the relationship of force required to the mass is linear or exponential? Or - putting it another way as players get heavier does the force required at the margin go up ?
Jon



_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. 1st semester was a long time ago. I know the equation I was just not thinking clearly.  Makes sense.


Subject: Re: [JudoList] judo physics **** question
Date: Monday, April 19, 2010, 6:51 PM

For the same acceleration, the force is proportional to the mass.  f=ma is a basic foundation of first-semester physics.

  -- Carl
.
  ----- Original Message -----
  From: Jonathan Jeffer
  To: Judo-L Judo-L
  Sent: Monday, April 19, 2010 6:47 PM
  Subject: [JudoList] judo physics **** question


  Okay - for the engineers and scientists on the list.
  I was thinking about this question -
  Its clear that it takes more energy (and greater force) to accelerate a heavier body than a smaller one. Also to stop heavier body already in motion. Does anyone know if the relationship of force required to the mass is linear or exponential? Or - putting it another way as players get heavier does the force required at the margin go up ?
  Jon


       
  _______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. I am not going to forward this to my dojo. I have nothing but engineers.
Including 2 MIT PhD's try to teach this group of people an art. I have said,
"throw to the perpendicular of the line that connects to the back of your
feet" so many times I get light headed every time I go to class. I even
started teaching throws as equations. aaaaaaaaaaaaaaHHHHHHHHHHHHHHHH

Richard Porro

If it isn't full contact, it isn't martial arts!
-----Original Message-----
From: judolist- [mailto:judolist-] On
Behalf Of Jonathan Jeffer
Sent: Monday, April 19, 2010 5:47 PM
To: Judo-L Judo-L
Subject: [JudoList] judo physics **** question

Okay - for the engineers and scientists on the list.
I was thinking about this question -
Its clear that it takes more energy (and greater force) to accelerate a
heavier body than a smaller one. Also to stop heavier body already in
motion.  Does anyone know if the relationship of force required to the mass
is linear or exponential?  Or - putting it another way as players get
heavier does the force required at the margin go up ?
Jon



_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. Sounds like Monday night class again.:)

Richard Porro

If it isn't full contact, it isn't martial arts!

-----Original Message-----
From: judolist- [mailto:judolist-] On
Behalf Of Carl Hayes
Sent: Monday, April 19, 2010 5:52 PM
To: Discussion of All Aspects of Traditional and Modern Judo
Subject: Re: [JudoList] judo physics **** question

For the same acceleration, the force is proportional to the mass. f=ma is a
basic foundation of first-semester physics.

-- Carl
.
----- Original Message -----
From: Jonathan Jeffer
To: Judo-L Judo-L
Sent: Monday, April 19, 2010 6:47 PM
Subject: [JudoList] judo physics **** question


Okay - for the engineers and scientists on the list.
I was thinking about this question -
Its clear that it takes more energy (and greater force) to accelerate a
heavier body than a smaller one. Also to stop heavier body already in
motion. Does anyone know if the relationship of force required to the mass
is linear or exponential? Or - putting it another way as players get heavier
does the force required at the margin go up ?
Jon



_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. What I was wondering about is something I have observed - that big people tend to accelerate slower and change direction slower  than smaller people.
The energy needed to accelerate more mass is clear.  What I was wonder about was whether it gets harder as mass goes up.  What Carl corrected me on is that its not actually harder, because the relationship is linear.  Other factors might not be linear.  Like the ratio of strength to mass.

--- On Tue, 4/20/10, Richard Porro <> wrote:

From: Richard Porro <>
Subject: Re: [JudoList] judo physics **** question
To: "'Discussion of All Aspects of Traditional and Modern Judo'" <>
Date: Tuesday, April 20, 2010, 11:19 AM

I am not going to forward this to my dojo. I have nothing but engineers.
Including 2 MIT PhD's try to teach this group of people an art. I have said,
"throw to the perpendicular of the line that connects to the back of your
feet" so many times I get light headed every time I go to class. I even
started teaching throws as equations. aaaaaaaaaaaaaaHHHHHHHHHHHHHHHH

Richard Porro

If it isn't full contact, it isn't martial arts!
-----Original Message-----
From: judolist- [mailto:judolist-] On
Behalf Of Jonathan Jeffer
Sent: Monday, April 19, 2010 5:47 PM
To: Judo-L Judo-L
Subject: [JudoList] judo physics **** question

Okay - for the engineers and scientists on the list.
I was thinking about this question -
Its clear that it takes more energy (and greater force) to accelerate a
heavier body than a smaller one. Also to stop heavier body already in
motion.  Does anyone know if the relationship of force required to the mass
is linear or exponential?  Or - putting it another way as players get
heavier does the force required at the margin go up ?
Jon


     
_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. You are correct. It takes longer for a larger person to arrive at the "sweet" spot of no return as my sensei used to say. Most people try to throw to soon and therefore have to force the engagement.


T Ryan





-----Original Message-----
From: Jonathan Jeffer <>
To: Discussion of All Aspects of Traditional and Modern Judo <>
Sent: Tue, Apr 20, 2010 12:10 pm
Subject: Re: [JudoList] judo physics **** question


What I was wondering about is something I have observed - that big people tend
to accelerate slower and change direction slower than smaller people.
The energy needed to accelerate more mass is clear. What I was wonder about was
whether it gets harder as mass goes up. What Carl corrected me on is that its
not actually harder, because the relationship is linear. Other factors might
not be linear. Like the ratio of strength to mass.

--- On Tue, 4/20/10, Richard Porro <> wrote:

From: Richard Porro <>
Subject: Re: [JudoList] judo physics **** question
To: "'Discussion of All Aspects of Traditional and Modern Judo'"
<>
Date: Tuesday, April 20, 2010, 11:19 AM

I am not going to forward this to my dojo. I have nothing but engineers.
Including 2 MIT PhD's try to teach this group of people an art. I have said,
"throw to the perpendicular of the line that connects to the back of your
feet" so many times I get light headed every time I go to class. I even
started teaching throws as equations. aaaaaaaaaaaaaaHHHHHHHHHHHHHHHH

Richard Porro

If it isn't full contact, it isn't martial arts!
-----Original Message-----
From: judolist- [mailto:judolist-] On
Behalf Of Jonathan Jeffer
Sent: Monday, April 19, 2010 5:47 PM
To: Judo-L Judo-L
Subject: [JudoList] judo physics **** question

Okay - for the engineers and scientists on the list.
I was thinking about this question -
Its clear that it takes more energy (and greater force) to accelerate a
heavier body than a smaller one. Also to stop heavier body already in
motion. Does anyone know if the relationship of force required to the mass
is linear or exponential? Or - putting it another way as players get
heavier does the force required at the margin go up ?
Jon



_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. Do they really accelerate slower? Or do they just have a greater distance to travel? But maybe they really do accelerate slower, because after all their mass is proportional to the cube of their height if they are of similar build -- very nonlinear.

So, for example, if you are 10% taller than I am (and built the same), you must move 10% farther, and you must move 33% more mass, too. So you'd better be 44% stronger if you want to move a body length in the same time I move a body length.

Yeah, I'll bet they accelerate slower.

-- Carl
.
----- Original Message -----
From: Jonathan Jeffer
To: Discussion of All Aspects of Traditional and Modern Judo
Sent: Tuesday, April 20, 2010 12:10 PM
Subject: Re: [JudoList] judo physics **** question


What I was wondering about is something I have observed - that big people tend to accelerate slower and change direction slower than smaller people.
The energy needed to accelerate more mass is clear. What I was wonder about was whether it gets harder as mass goes up. What Carl corrected me on is that its not actually harder, because the relationship is linear. Other factors might not be linear. Like the ratio of strength to mass.

--- On Tue, 4/20/10, Richard Porro <> wrote:

From: Richard Porro <>
Subject: Re: [JudoList] judo physics **** question
To: "'Discussion of All Aspects of Traditional and Modern Judo'" <>
Date: Tuesday, April 20, 2010, 11:19 AM

I am not going to forward this to my dojo. I have nothing but engineers.
Including 2 MIT PhD's try to teach this group of people an art. I have said,
"throw to the perpendicular of the line that connects to the back of your
feet" so many times I get light headed every time I go to class. I even
started teaching throws as equations. aaaaaaaaaaaaaaHHHHHHHHHHHHHHHH

Richard Porro

If it isn't full contact, it isn't martial arts!
-----Original Message-----
From: judolist- [mailto:judolist-] On
Behalf Of Jonathan Jeffer
Sent: Monday, April 19, 2010 5:47 PM
To: Judo-L Judo-L
Subject: [JudoList] judo physics **** question

Okay - for the engineers and scientists on the list.
I was thinking about this question -
Its clear that it takes more energy (and greater force) to accelerate a
heavier body than a smaller one. Also to stop heavier body already in
motion. Does anyone know if the relationship of force required to the mass
is linear or exponential? Or - putting it another way as players get
heavier does the force required at the margin go up ?
Jon



_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. That is true. They don't wait for the off balance and are forced to muscle
thru. Also another observation is that" big people" tend to force things
using brute strength first before they even try to off balance Uke.



Richard Porro



If it isn't full contact, it isn't martial arts!



-----Original Message-----
From: judolist- [mailto:judolist-] On
Behalf Of
Sent: Tuesday, April 20, 2010 11:23 AM
To:
Subject: Re: [JudoList] judo physics **** question



You are correct. It takes longer for a larger person to arrive at the
"sweet" spot of no return as my sensei used to say. Most people try to
throw to soon and therefore have to force the engagement.





T Ryan











-----Original Message-----

From: Jonathan Jeffer <>

To: Discussion of All Aspects of Traditional and Modern Judo
<>

Sent: Tue, Apr 20, 2010 12:10 pm

Subject: Re: [JudoList] judo physics **** question





What I was wondering about is something I have observed - that big people
tend

to accelerate slower and change direction slower than smaller people.

The energy needed to accelerate more mass is clear. What I was wonder about
was

whether it gets harder as mass goes up. What Carl corrected me on is that
its

not actually harder, because the relationship is linear. Other factors
might

not be linear. Like the ratio of strength to mass.



--- On Tue, 4/20/10, Richard Porro <> wrote:



From: Richard Porro <>

Subject: Re: [JudoList] judo physics **** question

To: "'Discussion of All Aspects of Traditional and Modern Judo'"

<>

Date: Tuesday, April 20, 2010, 11:19 AM



I am not going to forward this to my dojo. I have nothing but engineers.

Including 2 MIT PhD's try to teach this group of people an art. I have said,

"throw to the perpendicular of the line that connects to the back of your

feet" so many times I get light headed every time I go to class. I even

started teaching throws as equations. aaaaaaaaaaaaaaHHHHHHHHHHHHHHHH



Richard Porro



If it isn't full contact, it isn't martial arts!

-----Original Message-----

From: judolist- [mailto:judolist-] On

Behalf Of Jonathan Jeffer

Sent: Monday, April 19, 2010 5:47 PM

To: Judo-L Judo-L

Subject: [JudoList] judo physics **** question



Okay - for the engineers and scientists on the list.

I was thinking about this question -

Its clear that it takes more energy (and greater force) to accelerate a

heavier body than a smaller one. Also to stop heavier body already in

motion. Does anyone know if the relationship of force required to the mass

is linear or exponential? Or - putting it another way as players get

heavier does the force required at the margin go up ?

Jon







_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe.

Okay - for the engineers and scientists on the list.
I was thinking about this question -
Its clear that it takes more energy (and greater force) to accelerate a heavier body than a smaller one. Also to stop heavier body already in motion.  Does anyone know if the relationship of force required to the mass is linear or exponential?  Or - putting it another way as players get heavier does the force required at the margin go up ?
Jon



_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. For the same acceleration, the force is proportional to the mass. f=ma is a basic foundation of first-semester physics.

-- Carl
.
----- Original Message -----
From: Jonathan Jeffer
To: Judo-L Judo-L
Sent: Monday, April 19, 2010 6:47 PM
Subject: [JudoList] judo physics **** question


Okay - for the engineers and scientists on the list.
I was thinking about this question -
Its clear that it takes more energy (and greater force) to accelerate a heavier body than a smaller one. Also to stop heavier body already in motion. Does anyone know if the relationship of force required to the mass is linear or exponential? Or - putting it another way as players get heavier does the force required at the margin go up ?
Jon



_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. 1st semester was a long time ago. I know the equation I was just not thinking clearly.  Makes sense.


Subject: Re: [JudoList] judo physics **** question
Date: Monday, April 19, 2010, 6:51 PM

For the same acceleration, the force is proportional to the mass.  f=ma is a basic foundation of first-semester physics.

  -- Carl
.
  ----- Original Message -----
  From: Jonathan Jeffer
  To: Judo-L Judo-L
  Sent: Monday, April 19, 2010 6:47 PM
  Subject: [JudoList] judo physics **** question


  Okay - for the engineers and scientists on the list.
  I was thinking about this question -
  Its clear that it takes more energy (and greater force) to accelerate a heavier body than a smaller one. Also to stop heavier body already in motion. Does anyone know if the relationship of force required to the mass is linear or exponential? Or - putting it another way as players get heavier does the force required at the margin go up ?
  Jon


       
  _______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. I am not going to forward this to my dojo. I have nothing but engineers.
Including 2 MIT PhD's try to teach this group of people an art. I have said,
"throw to the perpendicular of the line that connects to the back of your
feet" so many times I get light headed every time I go to class. I even
started teaching throws as equations. aaaaaaaaaaaaaaHHHHHHHHHHHHHHHH

Richard Porro

If it isn't full contact, it isn't martial arts!
-----Original Message-----
From: judolist- [mailto:judolist-] On
Behalf Of Jonathan Jeffer
Sent: Monday, April 19, 2010 5:47 PM
To: Judo-L Judo-L
Subject: [JudoList] judo physics **** question

Okay - for the engineers and scientists on the list.
I was thinking about this question -
Its clear that it takes more energy (and greater force) to accelerate a
heavier body than a smaller one. Also to stop heavier body already in
motion.  Does anyone know if the relationship of force required to the mass
is linear or exponential?  Or - putting it another way as players get
heavier does the force required at the margin go up ?
Jon



_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. Sounds like Monday night class again.:)

Richard Porro

If it isn't full contact, it isn't martial arts!

-----Original Message-----
From: judolist- [mailto:judolist-] On
Behalf Of Carl Hayes
Sent: Monday, April 19, 2010 5:52 PM
To: Discussion of All Aspects of Traditional and Modern Judo
Subject: Re: [JudoList] judo physics **** question

For the same acceleration, the force is proportional to the mass. f=ma is a
basic foundation of first-semester physics.

-- Carl
.
----- Original Message -----
From: Jonathan Jeffer
To: Judo-L Judo-L
Sent: Monday, April 19, 2010 6:47 PM
Subject: [JudoList] judo physics **** question


Okay - for the engineers and scientists on the list.
I was thinking about this question -
Its clear that it takes more energy (and greater force) to accelerate a
heavier body than a smaller one. Also to stop heavier body already in
motion. Does anyone know if the relationship of force required to the mass
is linear or exponential? Or - putting it another way as players get heavier
does the force required at the margin go up ?
Jon



_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. What I was wondering about is something I have observed - that big people tend to accelerate slower and change direction slower  than smaller people.
The energy needed to accelerate more mass is clear.  What I was wonder about was whether it gets harder as mass goes up.  What Carl corrected me on is that its not actually harder, because the relationship is linear.  Other factors might not be linear.  Like the ratio of strength to mass.

--- On Tue, 4/20/10, Richard Porro <> wrote:

From: Richard Porro <>
Subject: Re: [JudoList] judo physics **** question
To: "'Discussion of All Aspects of Traditional and Modern Judo'" <>
Date: Tuesday, April 20, 2010, 11:19 AM

I am not going to forward this to my dojo. I have nothing but engineers.
Including 2 MIT PhD's try to teach this group of people an art. I have said,
"throw to the perpendicular of the line that connects to the back of your
feet" so many times I get light headed every time I go to class. I even
started teaching throws as equations. aaaaaaaaaaaaaaHHHHHHHHHHHHHHHH

Richard Porro

If it isn't full contact, it isn't martial arts!
-----Original Message-----
From: judolist- [mailto:judolist-] On
Behalf Of Jonathan Jeffer
Sent: Monday, April 19, 2010 5:47 PM
To: Judo-L Judo-L
Subject: [JudoList] judo physics **** question

Okay - for the engineers and scientists on the list.
I was thinking about this question -
Its clear that it takes more energy (and greater force) to accelerate a
heavier body than a smaller one. Also to stop heavier body already in
motion.  Does anyone know if the relationship of force required to the mass
is linear or exponential?  Or - putting it another way as players get
heavier does the force required at the margin go up ?
Jon


     
_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. You are correct. It takes longer for a larger person to arrive at the "sweet" spot of no return as my sensei used to say. Most people try to throw to soon and therefore have to force the engagement.


T Ryan





-----Original Message-----
From: Jonathan Jeffer <>
To: Discussion of All Aspects of Traditional and Modern Judo <>
Sent: Tue, Apr 20, 2010 12:10 pm
Subject: Re: [JudoList] judo physics **** question


What I was wondering about is something I have observed - that big people tend
to accelerate slower and change direction slower than smaller people.
The energy needed to accelerate more mass is clear. What I was wonder about was
whether it gets harder as mass goes up. What Carl corrected me on is that its
not actually harder, because the relationship is linear. Other factors might
not be linear. Like the ratio of strength to mass.

--- On Tue, 4/20/10, Richard Porro <> wrote:

From: Richard Porro <>
Subject: Re: [JudoList] judo physics **** question
To: "'Discussion of All Aspects of Traditional and Modern Judo'"
<>
Date: Tuesday, April 20, 2010, 11:19 AM

I am not going to forward this to my dojo. I have nothing but engineers.
Including 2 MIT PhD's try to teach this group of people an art. I have said,
"throw to the perpendicular of the line that connects to the back of your
feet" so many times I get light headed every time I go to class. I even
started teaching throws as equations. aaaaaaaaaaaaaaHHHHHHHHHHHHHHHH

Richard Porro

If it isn't full contact, it isn't martial arts!
-----Original Message-----
From: judolist- [mailto:judolist-] On
Behalf Of Jonathan Jeffer
Sent: Monday, April 19, 2010 5:47 PM
To: Judo-L Judo-L
Subject: [JudoList] judo physics **** question

Okay - for the engineers and scientists on the list.
I was thinking about this question -
Its clear that it takes more energy (and greater force) to accelerate a
heavier body than a smaller one. Also to stop heavier body already in
motion. Does anyone know if the relationship of force required to the mass
is linear or exponential? Or - putting it another way as players get
heavier does the force required at the margin go up ?
Jon



_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. Do they really accelerate slower? Or do they just have a greater distance to travel? But maybe they really do accelerate slower, because after all their mass is proportional to the cube of their height if they are of similar build -- very nonlinear.

So, for example, if you are 10% taller than I am (and built the same), you must move 10% farther, and you must move 33% more mass, too. So you'd better be 44% stronger if you want to move a body length in the same time I move a body length.

Yeah, I'll bet they accelerate slower.

-- Carl
.
----- Original Message -----
From: Jonathan Jeffer
To: Discussion of All Aspects of Traditional and Modern Judo
Sent: Tuesday, April 20, 2010 12:10 PM
Subject: Re: [JudoList] judo physics **** question


What I was wondering about is something I have observed - that big people tend to accelerate slower and change direction slower than smaller people.
The energy needed to accelerate more mass is clear. What I was wonder about was whether it gets harder as mass goes up. What Carl corrected me on is that its not actually harder, because the relationship is linear. Other factors might not be linear. Like the ratio of strength to mass.

--- On Tue, 4/20/10, Richard Porro <> wrote:

From: Richard Porro <>
Subject: Re: [JudoList] judo physics **** question
To: "'Discussion of All Aspects of Traditional and Modern Judo'" <>
Date: Tuesday, April 20, 2010, 11:19 AM

I am not going to forward this to my dojo. I have nothing but engineers.
Including 2 MIT PhD's try to teach this group of people an art. I have said,
"throw to the perpendicular of the line that connects to the back of your
feet" so many times I get light headed every time I go to class. I even
started teaching throws as equations. aaaaaaaaaaaaaaHHHHHHHHHHHHHHHH

Richard Porro

If it isn't full contact, it isn't martial arts!
-----Original Message-----
From: judolist- [mailto:judolist-] On
Behalf Of Jonathan Jeffer
Sent: Monday, April 19, 2010 5:47 PM
To: Judo-L Judo-L
Subject: [JudoList] judo physics **** question

Okay - for the engineers and scientists on the list.
I was thinking about this question -
Its clear that it takes more energy (and greater force) to accelerate a
heavier body than a smaller one. Also to stop heavier body already in
motion. Does anyone know if the relationship of force required to the mass
is linear or exponential? Or - putting it another way as players get
heavier does the force required at the margin go up ?
Jon



_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. That is true. They don't wait for the off balance and are forced to muscle
thru. Also another observation is that" big people" tend to force things
using brute strength first before they even try to off balance Uke.



Richard Porro



If it isn't full contact, it isn't martial arts!



-----Original Message-----
From: judolist- [mailto:judolist-] On
Behalf Of
Sent: Tuesday, April 20, 2010 11:23 AM
To:
Subject: Re: [JudoList] judo physics **** question



You are correct. It takes longer for a larger person to arrive at the
"sweet" spot of no return as my sensei used to say. Most people try to
throw to soon and therefore have to force the engagement.





T Ryan











-----Original Message-----

From: Jonathan Jeffer <>

To: Discussion of All Aspects of Traditional and Modern Judo
<>

Sent: Tue, Apr 20, 2010 12:10 pm

Subject: Re: [JudoList] judo physics **** question





What I was wondering about is something I have observed - that big people
tend

to accelerate slower and change direction slower than smaller people.

The energy needed to accelerate more mass is clear. What I was wonder about
was

whether it gets harder as mass goes up. What Carl corrected me on is that
its

not actually harder, because the relationship is linear. Other factors
might

not be linear. Like the ratio of strength to mass.



--- On Tue, 4/20/10, Richard Porro <> wrote:



From: Richard Porro <>

Subject: Re: [JudoList] judo physics **** question

To: "'Discussion of All Aspects of Traditional and Modern Judo'"

<>

Date: Tuesday, April 20, 2010, 11:19 AM



I am not going to forward this to my dojo. I have nothing but engineers.

Including 2 MIT PhD's try to teach this group of people an art. I have said,

"throw to the perpendicular of the line that connects to the back of your

feet" so many times I get light headed every time I go to class. I even

started teaching throws as equations. aaaaaaaaaaaaaaHHHHHHHHHHHHHHHH



Richard Porro



If it isn't full contact, it isn't martial arts!

-----Original Message-----

From: judolist- [mailto:judolist-] On

Behalf Of Jonathan Jeffer

Sent: Monday, April 19, 2010 5:47 PM

To: Judo-L Judo-L

Subject: [JudoList] judo physics **** question



Okay - for the engineers and scientists on the list.

I was thinking about this question -

Its clear that it takes more energy (and greater force) to accelerate a

heavier body than a smaller one. Also to stop heavier body already in

motion. Does anyone know if the relationship of force required to the mass

is linear or exponential? Or - putting it another way as players get

heavier does the force required at the margin go up ?

Jon







_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. Now THAT's funny, I don't care who you are...



On Tue, Apr 20, 2010 at 8:19 AM, Richard Porro <> wrote:

> I am not going to forward this to my dojo. I have nothing but engineers.
> Including 2 MIT PhD's try to teach this group of people an art. I have
> said,
> "throw to the perpendicular of the line that connects to the back of your
> feet" so many times I get light headed every time I go to class. I even
> started teaching throws as equations. aaaaaaaaaaaaaaHHHHHHHHHHHHHHHH
>
> Richard Porro
>
> If it isn't full contact, it isn't martial arts!
> -----Original Message-----
> From: judolist- [mailto:judolist-]
> On
> Behalf Of Jonathan Jeffer
> Sent: Monday, April 19, 2010 5:47 PM
> To: Judo-L Judo-L
> Subject: [JudoList] judo physics **** question
>
> Okay - for the engineers and scientists on the list.
> I was thinking about this question -
> Its clear that it takes more energy (and greater force) to accelerate a
> heavier body than a smaller one. Also to stop heavier body already in
> motion. Does anyone know if the relationship of force required to the mass
> is linear or exponential? Or - putting it another way as players get
> heavier does the force required at the margin go up ?
> Jon
>
>
>
> _______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe.

Okay - for the engineers and scientists on the list.
I was thinking about this question -
Its clear that it takes more energy (and greater force) to accelerate a heavier body than a smaller one. Also to stop heavier body already in motion.  Does anyone know if the relationship of force required to the mass is linear or exponential?  Or - putting it another way as players get heavier does the force required at the margin go up ?
Jon



_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. For the same acceleration, the force is proportional to the mass. f=ma is a basic foundation of first-semester physics.

-- Carl
.
----- Original Message -----
From: Jonathan Jeffer
To: Judo-L Judo-L
Sent: Monday, April 19, 2010 6:47 PM
Subject: [JudoList] judo physics **** question


Okay - for the engineers and scientists on the list.
I was thinking about this question -
Its clear that it takes more energy (and greater force) to accelerate a heavier body than a smaller one. Also to stop heavier body already in motion. Does anyone know if the relationship of force required to the mass is linear or exponential? Or - putting it another way as players get heavier does the force required at the margin go up ?
Jon



_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. 1st semester was a long time ago. I know the equation I was just not thinking clearly.  Makes sense.


Subject: Re: [JudoList] judo physics **** question
Date: Monday, April 19, 2010, 6:51 PM

For the same acceleration, the force is proportional to the mass.  f=ma is a basic foundation of first-semester physics.

  -- Carl
.
  ----- Original Message -----
  From: Jonathan Jeffer
  To: Judo-L Judo-L
  Sent: Monday, April 19, 2010 6:47 PM
  Subject: [JudoList] judo physics **** question


  Okay - for the engineers and scientists on the list.
  I was thinking about this question -
  Its clear that it takes more energy (and greater force) to accelerate a heavier body than a smaller one. Also to stop heavier body already in motion. Does anyone know if the relationship of force required to the mass is linear or exponential? Or - putting it another way as players get heavier does the force required at the margin go up ?
  Jon


       
  _______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. I am not going to forward this to my dojo. I have nothing but engineers.
Including 2 MIT PhD's try to teach this group of people an art. I have said,
"throw to the perpendicular of the line that connects to the back of your
feet" so many times I get light headed every time I go to class. I even
started teaching throws as equations. aaaaaaaaaaaaaaHHHHHHHHHHHHHHHH

Richard Porro

If it isn't full contact, it isn't martial arts!
-----Original Message-----
From: judolist- [mailto:judolist-] On
Behalf Of Jonathan Jeffer
Sent: Monday, April 19, 2010 5:47 PM
To: Judo-L Judo-L
Subject: [JudoList] judo physics **** question

Okay - for the engineers and scientists on the list.
I was thinking about this question -
Its clear that it takes more energy (and greater force) to accelerate a
heavier body than a smaller one. Also to stop heavier body already in
motion.  Does anyone know if the relationship of force required to the mass
is linear or exponential?  Or - putting it another way as players get
heavier does the force required at the margin go up ?
Jon



_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. Sounds like Monday night class again.:)

Richard Porro

If it isn't full contact, it isn't martial arts!

-----Original Message-----
From: judolist- [mailto:judolist-] On
Behalf Of Carl Hayes
Sent: Monday, April 19, 2010 5:52 PM
To: Discussion of All Aspects of Traditional and Modern Judo
Subject: Re: [JudoList] judo physics **** question

For the same acceleration, the force is proportional to the mass. f=ma is a
basic foundation of first-semester physics.

-- Carl
.
----- Original Message -----
From: Jonathan Jeffer
To: Judo-L Judo-L
Sent: Monday, April 19, 2010 6:47 PM
Subject: [JudoList] judo physics **** question


Okay - for the engineers and scientists on the list.
I was thinking about this question -
Its clear that it takes more energy (and greater force) to accelerate a
heavier body than a smaller one. Also to stop heavier body already in
motion. Does anyone know if the relationship of force required to the mass
is linear or exponential? Or - putting it another way as players get heavier
does the force required at the margin go up ?
Jon



_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. What I was wondering about is something I have observed - that big people tend to accelerate slower and change direction slower  than smaller people.
The energy needed to accelerate more mass is clear.  What I was wonder about was whether it gets harder as mass goes up.  What Carl corrected me on is that its not actually harder, because the relationship is linear.  Other factors might not be linear.  Like the ratio of strength to mass.

--- On Tue, 4/20/10, Richard Porro <> wrote:

From: Richard Porro <>
Subject: Re: [JudoList] judo physics **** question
To: "'Discussion of All Aspects of Traditional and Modern Judo'" <>
Date: Tuesday, April 20, 2010, 11:19 AM

I am not going to forward this to my dojo. I have nothing but engineers.
Including 2 MIT PhD's try to teach this group of people an art. I have said,
"throw to the perpendicular of the line that connects to the back of your
feet" so many times I get light headed every time I go to class. I even
started teaching throws as equations. aaaaaaaaaaaaaaHHHHHHHHHHHHHHHH

Richard Porro

If it isn't full contact, it isn't martial arts!
-----Original Message-----
From: judolist- [mailto:judolist-] On
Behalf Of Jonathan Jeffer
Sent: Monday, April 19, 2010 5:47 PM
To: Judo-L Judo-L
Subject: [JudoList] judo physics **** question

Okay - for the engineers and scientists on the list.
I was thinking about this question -
Its clear that it takes more energy (and greater force) to accelerate a
heavier body than a smaller one. Also to stop heavier body already in
motion.  Does anyone know if the relationship of force required to the mass
is linear or exponential?  Or - putting it another way as players get
heavier does the force required at the margin go up ?
Jon


     
_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. You are correct. It takes longer for a larger person to arrive at the "sweet" spot of no return as my sensei used to say. Most people try to throw to soon and therefore have to force the engagement.


T Ryan





-----Original Message-----
From: Jonathan Jeffer <>
To: Discussion of All Aspects of Traditional and Modern Judo <>
Sent: Tue, Apr 20, 2010 12:10 pm
Subject: Re: [JudoList] judo physics **** question


What I was wondering about is something I have observed - that big people tend
to accelerate slower and change direction slower than smaller people.
The energy needed to accelerate more mass is clear. What I was wonder about was
whether it gets harder as mass goes up. What Carl corrected me on is that its
not actually harder, because the relationship is linear. Other factors might
not be linear. Like the ratio of strength to mass.

--- On Tue, 4/20/10, Richard Porro <> wrote:

From: Richard Porro <>
Subject: Re: [JudoList] judo physics **** question
To: "'Discussion of All Aspects of Traditional and Modern Judo'"
<>
Date: Tuesday, April 20, 2010, 11:19 AM

I am not going to forward this to my dojo. I have nothing but engineers.
Including 2 MIT PhD's try to teach this group of people an art. I have said,
"throw to the perpendicular of the line that connects to the back of your
feet" so many times I get light headed every time I go to class. I even
started teaching throws as equations. aaaaaaaaaaaaaaHHHHHHHHHHHHHHHH

Richard Porro

If it isn't full contact, it isn't martial arts!
-----Original Message-----
From: judolist- [mailto:judolist-] On
Behalf Of Jonathan Jeffer
Sent: Monday, April 19, 2010 5:47 PM
To: Judo-L Judo-L
Subject: [JudoList] judo physics **** question

Okay - for the engineers and scientists on the list.
I was thinking about this question -
Its clear that it takes more energy (and greater force) to accelerate a
heavier body than a smaller one. Also to stop heavier body already in
motion. Does anyone know if the relationship of force required to the mass
is linear or exponential? Or - putting it another way as players get
heavier does the force required at the margin go up ?
Jon



_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. Do they really accelerate slower? Or do they just have a greater distance to travel? But maybe they really do accelerate slower, because after all their mass is proportional to the cube of their height if they are of similar build -- very nonlinear.

So, for example, if you are 10% taller than I am (and built the same), you must move 10% farther, and you must move 33% more mass, too. So you'd better be 44% stronger if you want to move a body length in the same time I move a body length.

Yeah, I'll bet they accelerate slower.

-- Carl
.
----- Original Message -----
From: Jonathan Jeffer
To: Discussion of All Aspects of Traditional and Modern Judo
Sent: Tuesday, April 20, 2010 12:10 PM
Subject: Re: [JudoList] judo physics **** question


What I was wondering about is something I have observed - that big people tend to accelerate slower and change direction slower than smaller people.
The energy needed to accelerate more mass is clear. What I was wonder about was whether it gets harder as mass goes up. What Carl corrected me on is that its not actually harder, because the relationship is linear. Other factors might not be linear. Like the ratio of strength to mass.

--- On Tue, 4/20/10, Richard Porro <> wrote:

From: Richard Porro <>
Subject: Re: [JudoList] judo physics **** question
To: "'Discussion of All Aspects of Traditional and Modern Judo'" <>
Date: Tuesday, April 20, 2010, 11:19 AM

I am not going to forward this to my dojo. I have nothing but engineers.
Including 2 MIT PhD's try to teach this group of people an art. I have said,
"throw to the perpendicular of the line that connects to the back of your
feet" so many times I get light headed every time I go to class. I even
started teaching throws as equations. aaaaaaaaaaaaaaHHHHHHHHHHHHHHHH

Richard Porro

If it isn't full contact, it isn't martial arts!
-----Original Message-----
From: judolist- [mailto:judolist-] On
Behalf Of Jonathan Jeffer
Sent: Monday, April 19, 2010 5:47 PM
To: Judo-L Judo-L
Subject: [JudoList] judo physics **** question

Okay - for the engineers and scientists on the list.
I was thinking about this question -
Its clear that it takes more energy (and greater force) to accelerate a
heavier body than a smaller one. Also to stop heavier body already in
motion. Does anyone know if the relationship of force required to the mass
is linear or exponential? Or - putting it another way as players get
heavier does the force required at the margin go up ?
Jon



_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. That is true. They don't wait for the off balance and are forced to muscle
thru. Also another observation is that" big people" tend to force things
using brute strength first before they even try to off balance Uke.



Richard Porro



If it isn't full contact, it isn't martial arts!



-----Original Message-----
From: judolist- [mailto:judolist-] On
Behalf Of
Sent: Tuesday, April 20, 2010 11:23 AM
To:
Subject: Re: [JudoList] judo physics **** question



You are correct. It takes longer for a larger person to arrive at the
"sweet" spot of no return as my sensei used to say. Most people try to
throw to soon and therefore have to force the engagement.





T Ryan











-----Original Message-----

From: Jonathan Jeffer <>

To: Discussion of All Aspects of Traditional and Modern Judo
<>

Sent: Tue, Apr 20, 2010 12:10 pm

Subject: Re: [JudoList] judo physics **** question





What I was wondering about is something I have observed - that big people
tend

to accelerate slower and change direction slower than smaller people.

The energy needed to accelerate more mass is clear. What I was wonder about
was

whether it gets harder as mass goes up. What Carl corrected me on is that
its

not actually harder, because the relationship is linear. Other factors
might

not be linear. Like the ratio of strength to mass.



--- On Tue, 4/20/10, Richard Porro <> wrote:



From: Richard Porro <>

Subject: Re: [JudoList] judo physics **** question

To: "'Discussion of All Aspects of Traditional and Modern Judo'"

<>

Date: Tuesday, April 20, 2010, 11:19 AM



I am not going to forward this to my dojo. I have nothing but engineers.

Including 2 MIT PhD's try to teach this group of people an art. I have said,

"throw to the perpendicular of the line that connects to the back of your

feet" so many times I get light headed every time I go to class. I even

started teaching throws as equations. aaaaaaaaaaaaaaHHHHHHHHHHHHHHHH



Richard Porro



If it isn't full contact, it isn't martial arts!

-----Original Message-----

From: judolist- [mailto:judolist-] On

Behalf Of Jonathan Jeffer

Sent: Monday, April 19, 2010 5:47 PM

To: Judo-L Judo-L

Subject: [JudoList] judo physics **** question



Okay - for the engineers and scientists on the list.

I was thinking about this question -

Its clear that it takes more energy (and greater force) to accelerate a

heavier body than a smaller one. Also to stop heavier body already in

motion. Does anyone know if the relationship of force required to the mass

is linear or exponential? Or - putting it another way as players get

heavier does the force required at the margin go up ?

Jon







_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. Now THAT's funny, I don't care who you are...



On Tue, Apr 20, 2010 at 8:19 AM, Richard Porro <> wrote:

> I am not going to forward this to my dojo. I have nothing but engineers.
> Including 2 MIT PhD's try to teach this group of people an art. I have
> said,
> "throw to the perpendicular of the line that connects to the back of your
> feet" so many times I get light headed every time I go to class. I even
> started teaching throws as equations. aaaaaaaaaaaaaaHHHHHHHHHHHHHHHH
>
> Richard Porro
>
> If it isn't full contact, it isn't martial arts!
> -----Original Message-----
> From: judolist- [mailto:judolist-]
> On
> Behalf Of Jonathan Jeffer
> Sent: Monday, April 19, 2010 5:47 PM
> To: Judo-L Judo-L
> Subject: [JudoList] judo physics **** question
>
> Okay - for the engineers and scientists on the list.
> I was thinking about this question -
> Its clear that it takes more energy (and greater force) to accelerate a
> heavier body than a smaller one. Also to stop heavier body already in
> motion. Does anyone know if the relationship of force required to the mass
> is linear or exponential? Or - putting it another way as players get
> heavier does the force required at the margin go up ?
> Jon
>
>
>
> _______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. Acceleration is force divided by mass. Greater mass equals lower acceleration. Newton's 2nd law.

-----Original Message-----
From: judolist- [mailto:judolist-] On Behalf Of Carl Hayes
Sent: Tuesday, April 20, 2010 12:29 PM
To: Discussion of All Aspects of Traditional and Modern Judo
Subject: Re: [JudoList] judo physics **** question

Do they really accelerate slower? Or do they just have a greater distance to travel? But maybe they really do accelerate slower, because after all their mass is proportional to the cube of their height if they are of similar build -- very nonlinear.

So, for example, if you are 10% taller than I am (and built the same), you must move 10% farther, and you must move 33% more mass, too. So you'd better be 44% stronger if you want to move a body length in the same time I move a body length.

Yeah, I'll bet they accelerate slower.

-- Carl
.
----- Original Message -----
From: Jonathan Jeffer
To: Discussion of All Aspects of Traditional and Modern Judo
Sent: Tuesday, April 20, 2010 12:10 PM
Subject: Re: [JudoList] judo physics **** question


What I was wondering about is something I have observed - that big people tend to accelerate slower and change direction slower than smaller people.
The energy needed to accelerate more mass is clear. What I was wonder about was whether it gets harder as mass goes up. What Carl corrected me on is that its not actually harder, because the relationship is linear. Other factors might not be linear. Like the ratio of strength to mass.

--- On Tue, 4/20/10, Richard Porro <> wrote:

From: Richard Porro <>
Subject: Re: [JudoList] judo physics **** question
To: "'Discussion of All Aspects of Traditional and Modern Judo'" <>
Date: Tuesday, April 20, 2010, 11:19 AM

I am not going to forward this to my dojo. I have nothing but engineers.
Including 2 MIT PhD's try to teach this group of people an art. I have said,
"throw to the perpendicular of the line that connects to the back of your
feet" so many times I get light headed every time I go to class. I even
started teaching throws as equations. aaaaaaaaaaaaaaHHHHHHHHHHHHHHHH

Richard Porro

If it isn't full contact, it isn't martial arts!
-----Original Message-----
From: judolist- [mailto:judolist-] On
Behalf Of Jonathan Jeffer
Sent: Monday, April 19, 2010 5:47 PM
To: Judo-L Judo-L
Subject: [JudoList] judo physics **** question

Okay - for the engineers and scientists on the list.
I was thinking about this question -
Its clear that it takes more energy (and greater force) to accelerate a
heavier body than a smaller one. Also to stop heavier body already in
motion. Does anyone know if the relationship of force required to the mass
is linear or exponential? Or - putting it another way as players get
heavier does the force required at the margin go up ?
Jon



_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe.

Okay - for the engineers and scientists on the list.
I was thinking about this question -
Its clear that it takes more energy (and greater force) to accelerate a heavier body than a smaller one. Also to stop heavier body already in motion.  Does anyone know if the relationship of force required to the mass is linear or exponential?  Or - putting it another way as players get heavier does the force required at the margin go up ?
Jon



_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. For the same acceleration, the force is proportional to the mass. f=ma is a basic foundation of first-semester physics.

-- Carl
.
----- Original Message -----
From: Jonathan Jeffer
To: Judo-L Judo-L
Sent: Monday, April 19, 2010 6:47 PM
Subject: [JudoList] judo physics **** question


Okay - for the engineers and scientists on the list.
I was thinking about this question -
Its clear that it takes more energy (and greater force) to accelerate a heavier body than a smaller one. Also to stop heavier body already in motion. Does anyone know if the relationship of force required to the mass is linear or exponential? Or - putting it another way as players get heavier does the force required at the margin go up ?
Jon



_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. 1st semester was a long time ago. I know the equation I was just not thinking clearly.  Makes sense.


Subject: Re: [JudoList] judo physics **** question
Date: Monday, April 19, 2010, 6:51 PM

For the same acceleration, the force is proportional to the mass.  f=ma is a basic foundation of first-semester physics.

  -- Carl
.
  ----- Original Message -----
  From: Jonathan Jeffer
  To: Judo-L Judo-L
  Sent: Monday, April 19, 2010 6:47 PM
  Subject: [JudoList] judo physics **** question


  Okay - for the engineers and scientists on the list.
  I was thinking about this question -
  Its clear that it takes more energy (and greater force) to accelerate a heavier body than a smaller one. Also to stop heavier body already in motion. Does anyone know if the relationship of force required to the mass is linear or exponential? Or - putting it another way as players get heavier does the force required at the margin go up ?
  Jon


       
  _______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. I am not going to forward this to my dojo. I have nothing but engineers.
Including 2 MIT PhD's try to teach this group of people an art. I have said,
"throw to the perpendicular of the line that connects to the back of your
feet" so many times I get light headed every time I go to class. I even
started teaching throws as equations. aaaaaaaaaaaaaaHHHHHHHHHHHHHHHH

Richard Porro

If it isn't full contact, it isn't martial arts!
-----Original Message-----
From: judolist- [mailto:judolist-] On
Behalf Of Jonathan Jeffer
Sent: Monday, April 19, 2010 5:47 PM
To: Judo-L Judo-L
Subject: [JudoList] judo physics **** question

Okay - for the engineers and scientists on the list.
I was thinking about this question -
Its clear that it takes more energy (and greater force) to accelerate a
heavier body than a smaller one. Also to stop heavier body already in
motion.  Does anyone know if the relationship of force required to the mass
is linear or exponential?  Or - putting it another way as players get
heavier does the force required at the margin go up ?
Jon



_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. Sounds like Monday night class again.:)

Richard Porro

If it isn't full contact, it isn't martial arts!

-----Original Message-----
From: judolist- [mailto:judolist-] On
Behalf Of Carl Hayes
Sent: Monday, April 19, 2010 5:52 PM
To: Discussion of All Aspects of Traditional and Modern Judo
Subject: Re: [JudoList] judo physics **** question

For the same acceleration, the force is proportional to the mass. f=ma is a
basic foundation of first-semester physics.

-- Carl
.
----- Original Message -----
From: Jonathan Jeffer
To: Judo-L Judo-L
Sent: Monday, April 19, 2010 6:47 PM
Subject: [JudoList] judo physics **** question


Okay - for the engineers and scientists on the list.
I was thinking about this question -
Its clear that it takes more energy (and greater force) to accelerate a
heavier body than a smaller one. Also to stop heavier body already in
motion. Does anyone know if the relationship of force required to the mass
is linear or exponential? Or - putting it another way as players get heavier
does the force required at the margin go up ?
Jon



_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. What I was wondering about is something I have observed - that big people tend to accelerate slower and change direction slower  than smaller people.
The energy needed to accelerate more mass is clear.  What I was wonder about was whether it gets harder as mass goes up.  What Carl corrected me on is that its not actually harder, because the relationship is linear.  Other factors might not be linear.  Like the ratio of strength to mass.

--- On Tue, 4/20/10, Richard Porro <> wrote:

From: Richard Porro <>
Subject: Re: [JudoList] judo physics **** question
To: "'Discussion of All Aspects of Traditional and Modern Judo'" <>
Date: Tuesday, April 20, 2010, 11:19 AM

I am not going to forward this to my dojo. I have nothing but engineers.
Including 2 MIT PhD's try to teach this group of people an art. I have said,
"throw to the perpendicular of the line that connects to the back of your
feet" so many times I get light headed every time I go to class. I even
started teaching throws as equations. aaaaaaaaaaaaaaHHHHHHHHHHHHHHHH

Richard Porro

If it isn't full contact, it isn't martial arts!
-----Original Message-----
From: judolist- [mailto:judolist-] On
Behalf Of Jonathan Jeffer
Sent: Monday, April 19, 2010 5:47 PM
To: Judo-L Judo-L
Subject: [JudoList] judo physics **** question

Okay - for the engineers and scientists on the list.
I was thinking about this question -
Its clear that it takes more energy (and greater force) to accelerate a
heavier body than a smaller one. Also to stop heavier body already in
motion.  Does anyone know if the relationship of force required to the mass
is linear or exponential?  Or - putting it another way as players get
heavier does the force required at the margin go up ?
Jon


     
_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. You are correct. It takes longer for a larger person to arrive at the "sweet" spot of no return as my sensei used to say. Most people try to throw to soon and therefore have to force the engagement.


T Ryan





-----Original Message-----
From: Jonathan Jeffer <>
To: Discussion of All Aspects of Traditional and Modern Judo <>
Sent: Tue, Apr 20, 2010 12:10 pm
Subject: Re: [JudoList] judo physics **** question


What I was wondering about is something I have observed - that big people tend
to accelerate slower and change direction slower than smaller people.
The energy needed to accelerate more mass is clear. What I was wonder about was
whether it gets harder as mass goes up. What Carl corrected me on is that its
not actually harder, because the relationship is linear. Other factors might
not be linear. Like the ratio of strength to mass.

--- On Tue, 4/20/10, Richard Porro <> wrote:

From: Richard Porro <>
Subject: Re: [JudoList] judo physics **** question
To: "'Discussion of All Aspects of Traditional and Modern Judo'"
<>
Date: Tuesday, April 20, 2010, 11:19 AM

I am not going to forward this to my dojo. I have nothing but engineers.
Including 2 MIT PhD's try to teach this group of people an art. I have said,
"throw to the perpendicular of the line that connects to the back of your
feet" so many times I get light headed every time I go to class. I even
started teaching throws as equations. aaaaaaaaaaaaaaHHHHHHHHHHHHHHHH

Richard Porro

If it isn't full contact, it isn't martial arts!
-----Original Message-----
From: judolist- [mailto:judolist-] On
Behalf Of Jonathan Jeffer
Sent: Monday, April 19, 2010 5:47 PM
To: Judo-L Judo-L
Subject: [JudoList] judo physics **** question

Okay - for the engineers and scientists on the list.
I was thinking about this question -
Its clear that it takes more energy (and greater force) to accelerate a
heavier body than a smaller one. Also to stop heavier body already in
motion. Does anyone know if the relationship of force required to the mass
is linear or exponential? Or - putting it another way as players get
heavier does the force required at the margin go up ?
Jon



_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. Do they really accelerate slower? Or do they just have a greater distance to travel? But maybe they really do accelerate slower, because after all their mass is proportional to the cube of their height if they are of similar build -- very nonlinear.

So, for example, if you are 10% taller than I am (and built the same), you must move 10% farther, and you must move 33% more mass, too. So you'd better be 44% stronger if you want to move a body length in the same time I move a body length.

Yeah, I'll bet they accelerate slower.

-- Carl
.
----- Original Message -----
From: Jonathan Jeffer
To: Discussion of All Aspects of Traditional and Modern Judo
Sent: Tuesday, April 20, 2010 12:10 PM
Subject: Re: [JudoList] judo physics **** question


What I was wondering about is something I have observed - that big people tend to accelerate slower and change direction slower than smaller people.
The energy needed to accelerate more mass is clear. What I was wonder about was whether it gets harder as mass goes up. What Carl corrected me on is that its not actually harder, because the relationship is linear. Other factors might not be linear. Like the ratio of strength to mass.

--- On Tue, 4/20/10, Richard Porro <> wrote:

From: Richard Porro <>
Subject: Re: [JudoList] judo physics **** question
To: "'Discussion of All Aspects of Traditional and Modern Judo'" <>
Date: Tuesday, April 20, 2010, 11:19 AM

I am not going to forward this to my dojo. I have nothing but engineers.
Including 2 MIT PhD's try to teach this group of people an art. I have said,
"throw to the perpendicular of the line that connects to the back of your
feet" so many times I get light headed every time I go to class. I even
started teaching throws as equations. aaaaaaaaaaaaaaHHHHHHHHHHHHHHHH

Richard Porro

If it isn't full contact, it isn't martial arts!
-----Original Message-----
From: judolist- [mailto:judolist-] On
Behalf Of Jonathan Jeffer
Sent: Monday, April 19, 2010 5:47 PM
To: Judo-L Judo-L
Subject: [JudoList] judo physics **** question

Okay - for the engineers and scientists on the list.
I was thinking about this question -
Its clear that it takes more energy (and greater force) to accelerate a
heavier body than a smaller one. Also to stop heavier body already in
motion. Does anyone know if the relationship of force required to the mass
is linear or exponential? Or - putting it another way as players get
heavier does the force required at the margin go up ?
Jon



_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. That is true. They don't wait for the off balance and are forced to muscle
thru. Also another observation is that" big people" tend to force things
using brute strength first before they even try to off balance Uke.



Richard Porro



If it isn't full contact, it isn't martial arts!



-----Original Message-----
From: judolist- [mailto:judolist-] On
Behalf Of
Sent: Tuesday, April 20, 2010 11:23 AM
To:
Subject: Re: [JudoList] judo physics **** question



You are correct. It takes longer for a larger person to arrive at the
"sweet" spot of no return as my sensei used to say. Most people try to
throw to soon and therefore have to force the engagement.





T Ryan











-----Original Message-----

From: Jonathan Jeffer <>

To: Discussion of All Aspects of Traditional and Modern Judo
<>

Sent: Tue, Apr 20, 2010 12:10 pm

Subject: Re: [JudoList] judo physics **** question





What I was wondering about is something I have observed - that big people
tend

to accelerate slower and change direction slower than smaller people.

The energy needed to accelerate more mass is clear. What I was wonder about
was

whether it gets harder as mass goes up. What Carl corrected me on is that
its

not actually harder, because the relationship is linear. Other factors
might

not be linear. Like the ratio of strength to mass.



--- On Tue, 4/20/10, Richard Porro <> wrote:



From: Richard Porro <>

Subject: Re: [JudoList] judo physics **** question

To: "'Discussion of All Aspects of Traditional and Modern Judo'"

<>

Date: Tuesday, April 20, 2010, 11:19 AM



I am not going to forward this to my dojo. I have nothing but engineers.

Including 2 MIT PhD's try to teach this group of people an art. I have said,

"throw to the perpendicular of the line that connects to the back of your

feet" so many times I get light headed every time I go to class. I even

started teaching throws as equations. aaaaaaaaaaaaaaHHHHHHHHHHHHHHHH



Richard Porro



If it isn't full contact, it isn't martial arts!

-----Original Message-----

From: judolist- [mailto:judolist-] On

Behalf Of Jonathan Jeffer

Sent: Monday, April 19, 2010 5:47 PM

To: Judo-L Judo-L

Subject: [JudoList] judo physics **** question



Okay - for the engineers and scientists on the list.

I was thinking about this question -

Its clear that it takes more energy (and greater force) to accelerate a

heavier body than a smaller one. Also to stop heavier body already in

motion. Does anyone know if the relationship of force required to the mass

is linear or exponential? Or - putting it another way as players get

heavier does the force required at the margin go up ?

Jon







_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. Now THAT's funny, I don't care who you are...



On Tue, Apr 20, 2010 at 8:19 AM, Richard Porro <> wrote:

> I am not going to forward this to my dojo. I have nothing but engineers.
> Including 2 MIT PhD's try to teach this group of people an art. I have
> said,
> "throw to the perpendicular of the line that connects to the back of your
> feet" so many times I get light headed every time I go to class. I even
> started teaching throws as equations. aaaaaaaaaaaaaaHHHHHHHHHHHHHHHH
>
> Richard Porro
>
> If it isn't full contact, it isn't martial arts!
> -----Original Message-----
> From: judolist- [mailto:judolist-]
> On
> Behalf Of Jonathan Jeffer
> Sent: Monday, April 19, 2010 5:47 PM
> To: Judo-L Judo-L
> Subject: [JudoList] judo physics **** question
>
> Okay - for the engineers and scientists on the list.
> I was thinking about this question -
> Its clear that it takes more energy (and greater force) to accelerate a
> heavier body than a smaller one. Also to stop heavier body already in
> motion. Does anyone know if the relationship of force required to the mass
> is linear or exponential? Or - putting it another way as players get
> heavier does the force required at the margin go up ?
> Jon
>
>
>
> _______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. Acceleration is force divided by mass. Greater mass equals lower acceleration. Newton's 2nd law.

-----Original Message-----
From: judolist- [mailto:judolist-] On Behalf Of Carl Hayes
Sent: Tuesday, April 20, 2010 12:29 PM
To: Discussion of All Aspects of Traditional and Modern Judo
Subject: Re: [JudoList] judo physics **** question

Do they really accelerate slower? Or do they just have a greater distance to travel? But maybe they really do accelerate slower, because after all their mass is proportional to the cube of their height if they are of similar build -- very nonlinear.

So, for example, if you are 10% taller than I am (and built the same), you must move 10% farther, and you must move 33% more mass, too. So you'd better be 44% stronger if you want to move a body length in the same time I move a body length.

Yeah, I'll bet they accelerate slower.

-- Carl
.
----- Original Message -----
From: Jonathan Jeffer
To: Discussion of All Aspects of Traditional and Modern Judo
Sent: Tuesday, April 20, 2010 12:10 PM
Subject: Re: [JudoList] judo physics **** question


What I was wondering about is something I have observed - that big people tend to accelerate slower and change direction slower than smaller people.
The energy needed to accelerate more mass is clear. What I was wonder about was whether it gets harder as mass goes up. What Carl corrected me on is that its not actually harder, because the relationship is linear. Other factors might not be linear. Like the ratio of strength to mass.

--- On Tue, 4/20/10, Richard Porro <> wrote:

From: Richard Porro <>
Subject: Re: [JudoList] judo physics **** question
To: "'Discussion of All Aspects of Traditional and Modern Judo'" <>
Date: Tuesday, April 20, 2010, 11:19 AM

I am not going to forward this to my dojo. I have nothing but engineers.
Including 2 MIT PhD's try to teach this group of people an art. I have said,
"throw to the perpendicular of the line that connects to the back of your
feet" so many times I get light headed every time I go to class. I even
started teaching throws as equations. aaaaaaaaaaaaaaHHHHHHHHHHHHHHHH

Richard Porro

If it isn't full contact, it isn't martial arts!
-----Original Message-----
From: judolist- [mailto:judolist-] On
Behalf Of Jonathan Jeffer
Sent: Monday, April 19, 2010 5:47 PM
To: Judo-L Judo-L
Subject: [JudoList] judo physics **** question

Okay - for the engineers and scientists on the list.
I was thinking about this question -
Its clear that it takes more energy (and greater force) to accelerate a
heavier body than a smaller one. Also to stop heavier body already in
motion. Does anyone know if the relationship of force required to the mass
is linear or exponential? Or - putting it another way as players get
heavier does the force required at the margin go up ?
Jon



_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. See, I knew this would happen, it sounds just like my judo class. 3 minutes
of demonstration. 15 minutes of the math behind it.

Richard Porro

If it isn't full contact, it isn't martial arts!

-----Original Message-----
From: judolist- [mailto:judolist-] On
Behalf Of Carl Hayes
Sent: Tuesday, April 20, 2010 11:29 AM
To: Discussion of All Aspects of Traditional and Modern Judo
Subject: Re: [JudoList] judo physics **** question

Do they really accelerate slower? Or do they just have a greater distance
to travel? But maybe they really do accelerate slower, because after all
their mass is proportional to the cube of their height if they are of
similar build -- very nonlinear.

So, for example, if you are 10% taller than I am (and built the same), you
must move 10% farther, and you must move 33% more mass, too. So you'd
better be 44% stronger if you want to move a body length in the same time I
move a body length.

Yeah, I'll bet they accelerate slower.

-- Carl
.
----- Original Message -----
From: Jonathan Jeffer
To: Discussion of All Aspects of Traditional and Modern Judo
Sent: Tuesday, April 20, 2010 12:10 PM
Subject: Re: [JudoList] judo physics **** question


What I was wondering about is something I have observed - that big people
tend to accelerate slower and change direction slower than smaller people.
The energy needed to accelerate more mass is clear. What I was wonder
about was whether it gets harder as mass goes up. What Carl corrected me on
is that its not actually harder, because the relationship is linear. Other
factors might not be linear. Like the ratio of strength to mass.

--- On Tue, 4/20/10, Richard Porro <> wrote:

From: Richard Porro <>
Subject: Re: [JudoList] judo physics **** question
To: "'Discussion of All Aspects of Traditional and Modern Judo'"
<>
Date: Tuesday, April 20, 2010, 11:19 AM

I am not going to forward this to my dojo. I have nothing but engineers.
Including 2 MIT PhD's try to teach this group of people an art. I have
said,
"throw to the perpendicular of the line that connects to the back of your
feet" so many times I get light headed every time I go to class. I even
started teaching throws as equations. aaaaaaaaaaaaaaHHHHHHHHHHHHHHHH

Richard Porro

If it isn't full contact, it isn't martial arts!
-----Original Message-----
From: judolist- [mailto:judolist-]
On
Behalf Of Jonathan Jeffer
Sent: Monday, April 19, 2010 5:47 PM
To: Judo-L Judo-L
Subject: [JudoList] judo physics **** question

Okay - for the engineers and scientists on the list.
I was thinking about this question -
Its clear that it takes more energy (and greater force) to accelerate a
heavier body than a smaller one. Also to stop heavier body already in
motion. Does anyone know if the relationship of force required to the mass
is linear or exponential? Or - putting it another way as players get
heavier does the force required at the margin go up ?
Jon



_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe.

Okay - for the engineers and scientists on the list.
I was thinking about this question -
Its clear that it takes more energy (and greater force) to accelerate a heavier body than a smaller one. Also to stop heavier body already in motion.  Does anyone know if the relationship of force required to the mass is linear or exponential?  Or - putting it another way as players get heavier does the force required at the margin go up ?
Jon



_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. For the same acceleration, the force is proportional to the mass. f=ma is a basic foundation of first-semester physics.

-- Carl
.
----- Original Message -----
From: Jonathan Jeffer
To: Judo-L Judo-L
Sent: Monday, April 19, 2010 6:47 PM
Subject: [JudoList] judo physics **** question


Okay - for the engineers and scientists on the list.
I was thinking about this question -
Its clear that it takes more energy (and greater force) to accelerate a heavier body than a smaller one. Also to stop heavier body already in motion. Does anyone know if the relationship of force required to the mass is linear or exponential? Or - putting it another way as players get heavier does the force required at the margin go up ?
Jon



_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. 1st semester was a long time ago. I know the equation I was just not thinking clearly.  Makes sense.


Subject: Re: [JudoList] judo physics **** question
Date: Monday, April 19, 2010, 6:51 PM

For the same acceleration, the force is proportional to the mass.  f=ma is a basic foundation of first-semester physics.

  -- Carl
.
  ----- Original Message -----
  From: Jonathan Jeffer
  To: Judo-L Judo-L
  Sent: Monday, April 19, 2010 6:47 PM
  Subject: [JudoList] judo physics **** question


  Okay - for the engineers and scientists on the list.
  I was thinking about this question -
  Its clear that it takes more energy (and greater force) to accelerate a heavier body than a smaller one. Also to stop heavier body already in motion. Does anyone know if the relationship of force required to the mass is linear or exponential? Or - putting it another way as players get heavier does the force required at the margin go up ?
  Jon


       
  _______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. I am not going to forward this to my dojo. I have nothing but engineers.
Including 2 MIT PhD's try to teach this group of people an art. I have said,
"throw to the perpendicular of the line that connects to the back of your
feet" so many times I get light headed every time I go to class. I even
started teaching throws as equations. aaaaaaaaaaaaaaHHHHHHHHHHHHHHHH

Richard Porro

If it isn't full contact, it isn't martial arts!
-----Original Message-----
From: judolist- [mailto:judolist-] On
Behalf Of Jonathan Jeffer
Sent: Monday, April 19, 2010 5:47 PM
To: Judo-L Judo-L
Subject: [JudoList] judo physics **** question

Okay - for the engineers and scientists on the list.
I was thinking about this question -
Its clear that it takes more energy (and greater force) to accelerate a
heavier body than a smaller one. Also to stop heavier body already in
motion.  Does anyone know if the relationship of force required to the mass
is linear or exponential?  Or - putting it another way as players get
heavier does the force required at the margin go up ?
Jon



_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. Sounds like Monday night class again.:)

Richard Porro

If it isn't full contact, it isn't martial arts!

-----Original Message-----
From: judolist- [mailto:judolist-] On
Behalf Of Carl Hayes
Sent: Monday, April 19, 2010 5:52 PM
To: Discussion of All Aspects of Traditional and Modern Judo
Subject: Re: [JudoList] judo physics **** question

For the same acceleration, the force is proportional to the mass. f=ma is a
basic foundation of first-semester physics.

-- Carl
.
----- Original Message -----
From: Jonathan Jeffer
To: Judo-L Judo-L
Sent: Monday, April 19, 2010 6:47 PM
Subject: [JudoList] judo physics **** question


Okay - for the engineers and scientists on the list.
I was thinking about this question -
Its clear that it takes more energy (and greater force) to accelerate a
heavier body than a smaller one. Also to stop heavier body already in
motion. Does anyone know if the relationship of force required to the mass
is linear or exponential? Or - putting it another way as players get heavier
does the force required at the margin go up ?
Jon



_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. What I was wondering about is something I have observed - that big people tend to accelerate slower and change direction slower  than smaller people.
The energy needed to accelerate more mass is clear.  What I was wonder about was whether it gets harder as mass goes up.  What Carl corrected me on is that its not actually harder, because the relationship is linear.  Other factors might not be linear.  Like the ratio of strength to mass.

--- On Tue, 4/20/10, Richard Porro <> wrote:

From: Richard Porro <>
Subject: Re: [JudoList] judo physics **** question
To: "'Discussion of All Aspects of Traditional and Modern Judo'" <>
Date: Tuesday, April 20, 2010, 11:19 AM

I am not going to forward this to my dojo. I have nothing but engineers.
Including 2 MIT PhD's try to teach this group of people an art. I have said,
"throw to the perpendicular of the line that connects to the back of your
feet" so many times I get light headed every time I go to class. I even
started teaching throws as equations. aaaaaaaaaaaaaaHHHHHHHHHHHHHHHH

Richard Porro

If it isn't full contact, it isn't martial arts!
-----Original Message-----
From: judolist- [mailto:judolist-] On
Behalf Of Jonathan Jeffer
Sent: Monday, April 19, 2010 5:47 PM
To: Judo-L Judo-L
Subject: [JudoList] judo physics **** question

Okay - for the engineers and scientists on the list.
I was thinking about this question -
Its clear that it takes more energy (and greater force) to accelerate a
heavier body than a smaller one. Also to stop heavier body already in
motion.  Does anyone know if the relationship of force required to the mass
is linear or exponential?  Or - putting it another way as players get
heavier does the force required at the margin go up ?
Jon


     
_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. You are correct. It takes longer for a larger person to arrive at the "sweet" spot of no return as my sensei used to say. Most people try to throw to soon and therefore have to force the engagement.


T Ryan





-----Original Message-----
From: Jonathan Jeffer <>
To: Discussion of All Aspects of Traditional and Modern Judo <>
Sent: Tue, Apr 20, 2010 12:10 pm
Subject: Re: [JudoList] judo physics **** question


What I was wondering about is something I have observed - that big people tend
to accelerate slower and change direction slower than smaller people.
The energy needed to accelerate more mass is clear. What I was wonder about was
whether it gets harder as mass goes up. What Carl corrected me on is that its
not actually harder, because the relationship is linear. Other factors might
not be linear. Like the ratio of strength to mass.

--- On Tue, 4/20/10, Richard Porro <> wrote:

From: Richard Porro <>
Subject: Re: [JudoList] judo physics **** question
To: "'Discussion of All Aspects of Traditional and Modern Judo'"
<>
Date: Tuesday, April 20, 2010, 11:19 AM

I am not going to forward this to my dojo. I have nothing but engineers.
Including 2 MIT PhD's try to teach this group of people an art. I have said,
"throw to the perpendicular of the line that connects to the back of your
feet" so many times I get light headed every time I go to class. I even
started teaching throws as equations. aaaaaaaaaaaaaaHHHHHHHHHHHHHHHH

Richard Porro

If it isn't full contact, it isn't martial arts!
-----Original Message-----
From: judolist- [mailto:judolist-] On
Behalf Of Jonathan Jeffer
Sent: Monday, April 19, 2010 5:47 PM
To: Judo-L Judo-L
Subject: [JudoList] judo physics **** question

Okay - for the engineers and scientists on the list.
I was thinking about this question -
Its clear that it takes more energy (and greater force) to accelerate a
heavier body than a smaller one. Also to stop heavier body already in
motion. Does anyone know if the relationship of force required to the mass
is linear or exponential? Or - putting it another way as players get
heavier does the force required at the margin go up ?
Jon



_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. Do they really accelerate slower? Or do they just have a greater distance to travel? But maybe they really do accelerate slower, because after all their mass is proportional to the cube of their height if they are of similar build -- very nonlinear.

So, for example, if you are 10% taller than I am (and built the same), you must move 10% farther, and you must move 33% more mass, too. So you'd better be 44% stronger if you want to move a body length in the same time I move a body length.

Yeah, I'll bet they accelerate slower.

-- Carl
.
----- Original Message -----
From: Jonathan Jeffer
To: Discussion of All Aspects of Traditional and Modern Judo
Sent: Tuesday, April 20, 2010 12:10 PM
Subject: Re: [JudoList] judo physics **** question


What I was wondering about is something I have observed - that big people tend to accelerate slower and change direction slower than smaller people.
The energy needed to accelerate more mass is clear. What I was wonder about was whether it gets harder as mass goes up. What Carl corrected me on is that its not actually harder, because the relationship is linear. Other factors might not be linear. Like the ratio of strength to mass.

--- On Tue, 4/20/10, Richard Porro <> wrote:

From: Richard Porro <>
Subject: Re: [JudoList] judo physics **** question
To: "'Discussion of All Aspects of Traditional and Modern Judo'" <>
Date: Tuesday, April 20, 2010, 11:19 AM

I am not going to forward this to my dojo. I have nothing but engineers.
Including 2 MIT PhD's try to teach this group of people an art. I have said,
"throw to the perpendicular of the line that connects to the back of your
feet" so many times I get light headed every time I go to class. I even
started teaching throws as equations. aaaaaaaaaaaaaaHHHHHHHHHHHHHHHH

Richard Porro

If it isn't full contact, it isn't martial arts!
-----Original Message-----
From: judolist- [mailto:judolist-] On
Behalf Of Jonathan Jeffer
Sent: Monday, April 19, 2010 5:47 PM
To: Judo-L Judo-L
Subject: [JudoList] judo physics **** question

Okay - for the engineers and scientists on the list.
I was thinking about this question -
Its clear that it takes more energy (and greater force) to accelerate a
heavier body than a smaller one. Also to stop heavier body already in
motion. Does anyone know if the relationship of force required to the mass
is linear or exponential? Or - putting it another way as players get
heavier does the force required at the margin go up ?
Jon



_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. That is true. They don't wait for the off balance and are forced to muscle
thru. Also another observation is that" big people" tend to force things
using brute strength first before they even try to off balance Uke.



Richard Porro



If it isn't full contact, it isn't martial arts!



-----Original Message-----
From: judolist- [mailto:judolist-] On
Behalf Of
Sent: Tuesday, April 20, 2010 11:23 AM
To:
Subject: Re: [JudoList] judo physics **** question



You are correct. It takes longer for a larger person to arrive at the
"sweet" spot of no return as my sensei used to say. Most people try to
throw to soon and therefore have to force the engagement.





T Ryan











-----Original Message-----

From: Jonathan Jeffer <>

To: Discussion of All Aspects of Traditional and Modern Judo
<>

Sent: Tue, Apr 20, 2010 12:10 pm

Subject: Re: [JudoList] judo physics **** question





What I was wondering about is something I have observed - that big people
tend

to accelerate slower and change direction slower than smaller people.

The energy needed to accelerate more mass is clear. What I was wonder about
was

whether it gets harder as mass goes up. What Carl corrected me on is that
its

not actually harder, because the relationship is linear. Other factors
might

not be linear. Like the ratio of strength to mass.



--- On Tue, 4/20/10, Richard Porro <> wrote:



From: Richard Porro <>

Subject: Re: [JudoList] judo physics **** question

To: "'Discussion of All Aspects of Traditional and Modern Judo'"

<>

Date: Tuesday, April 20, 2010, 11:19 AM



I am not going to forward this to my dojo. I have nothing but engineers.

Including 2 MIT PhD's try to teach this group of people an art. I have said,

"throw to the perpendicular of the line that connects to the back of your

feet" so many times I get light headed every time I go to class. I even

started teaching throws as equations. aaaaaaaaaaaaaaHHHHHHHHHHHHHHHH



Richard Porro



If it isn't full contact, it isn't martial arts!

-----Original Message-----

From: judolist- [mailto:judolist-] On

Behalf Of Jonathan Jeffer

Sent: Monday, April 19, 2010 5:47 PM

To: Judo-L Judo-L

Subject: [JudoList] judo physics **** question



Okay - for the engineers and scientists on the list.

I was thinking about this question -

Its clear that it takes more energy (and greater force) to accelerate a

heavier body than a smaller one. Also to stop heavier body already in

motion. Does anyone know if the relationship of force required to the mass

is linear or exponential? Or - putting it another way as players get

heavier does the force required at the margin go up ?

Jon







_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. Now THAT's funny, I don't care who you are...



On Tue, Apr 20, 2010 at 8:19 AM, Richard Porro <> wrote:

> I am not going to forward this to my dojo. I have nothing but engineers.
> Including 2 MIT PhD's try to teach this group of people an art. I have
> said,
> "throw to the perpendicular of the line that connects to the back of your
> feet" so many times I get light headed every time I go to class. I even
> started teaching throws as equations. aaaaaaaaaaaaaaHHHHHHHHHHHHHHHH
>
> Richard Porro
>
> If it isn't full contact, it isn't martial arts!
> -----Original Message-----
> From: judolist- [mailto:judolist-]
> On
> Behalf Of Jonathan Jeffer
> Sent: Monday, April 19, 2010 5:47 PM
> To: Judo-L Judo-L
> Subject: [JudoList] judo physics **** question
>
> Okay - for the engineers and scientists on the list.
> I was thinking about this question -
> Its clear that it takes more energy (and greater force) to accelerate a
> heavier body than a smaller one. Also to stop heavier body already in
> motion. Does anyone know if the relationship of force required to the mass
> is linear or exponential? Or - putting it another way as players get
> heavier does the force required at the margin go up ?
> Jon
>
>
>
> _______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. Acceleration is force divided by mass. Greater mass equals lower acceleration. Newton's 2nd law.

-----Original Message-----
From: judolist- [mailto:judolist-] On Behalf Of Carl Hayes
Sent: Tuesday, April 20, 2010 12:29 PM
To: Discussion of All Aspects of Traditional and Modern Judo
Subject: Re: [JudoList] judo physics **** question

Do they really accelerate slower? Or do they just have a greater distance to travel? But maybe they really do accelerate slower, because after all their mass is proportional to the cube of their height if they are of similar build -- very nonlinear.

So, for example, if you are 10% taller than I am (and built the same), you must move 10% farther, and you must move 33% more mass, too. So you'd better be 44% stronger if you want to move a body length in the same time I move a body length.

Yeah, I'll bet they accelerate slower.

-- Carl
.
----- Original Message -----
From: Jonathan Jeffer
To: Discussion of All Aspects of Traditional and Modern Judo
Sent: Tuesday, April 20, 2010 12:10 PM
Subject: Re: [JudoList] judo physics **** question


What I was wondering about is something I have observed - that big people tend to accelerate slower and change direction slower than smaller people.
The energy needed to accelerate more mass is clear. What I was wonder about was whether it gets harder as mass goes up. What Carl corrected me on is that its not actually harder, because the relationship is linear. Other factors might not be linear. Like the ratio of strength to mass.

--- On Tue, 4/20/10, Richard Porro <> wrote:

From: Richard Porro <>
Subject: Re: [JudoList] judo physics **** question
To: "'Discussion of All Aspects of Traditional and Modern Judo'" <>
Date: Tuesday, April 20, 2010, 11:19 AM

I am not going to forward this to my dojo. I have nothing but engineers.
Including 2 MIT PhD's try to teach this group of people an art. I have said,
"throw to the perpendicular of the line that connects to the back of your
feet" so many times I get light headed every time I go to class. I even
started teaching throws as equations. aaaaaaaaaaaaaaHHHHHHHHHHHHHHHH

Richard Porro

If it isn't full contact, it isn't martial arts!
-----Original Message-----
From: judolist- [mailto:judolist-] On
Behalf Of Jonathan Jeffer
Sent: Monday, April 19, 2010 5:47 PM
To: Judo-L Judo-L
Subject: [JudoList] judo physics **** question

Okay - for the engineers and scientists on the list.
I was thinking about this question -
Its clear that it takes more energy (and greater force) to accelerate a
heavier body than a smaller one. Also to stop heavier body already in
motion. Does anyone know if the relationship of force required to the mass
is linear or exponential? Or - putting it another way as players get
heavier does the force required at the margin go up ?
Jon



_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. See, I knew this would happen, it sounds just like my judo class. 3 minutes
of demonstration. 15 minutes of the math behind it.

Richard Porro

If it isn't full contact, it isn't martial arts!

-----Original Message-----
From: judolist- [mailto:judolist-] On
Behalf Of Carl Hayes
Sent: Tuesday, April 20, 2010 11:29 AM
To: Discussion of All Aspects of Traditional and Modern Judo
Subject: Re: [JudoList] judo physics **** question

Do they really accelerate slower? Or do they just have a greater distance
to travel? But maybe they really do accelerate slower, because after all
their mass is proportional to the cube of their height if they are of
similar build -- very nonlinear.

So, for example, if you are 10% taller than I am (and built the same), you
must move 10% farther, and you must move 33% more mass, too. So you'd
better be 44% stronger if you want to move a body length in the same time I
move a body length.

Yeah, I'll bet they accelerate slower.

-- Carl
.
----- Original Message -----
From: Jonathan Jeffer
To: Discussion of All Aspects of Traditional and Modern Judo
Sent: Tuesday, April 20, 2010 12:10 PM
Subject: Re: [JudoList] judo physics **** question


What I was wondering about is something I have observed - that big people
tend to accelerate slower and change direction slower than smaller people.
The energy needed to accelerate more mass is clear. What I was wonder
about was whether it gets harder as mass goes up. What Carl corrected me on
is that its not actually harder, because the relationship is linear. Other
factors might not be linear. Like the ratio of strength to mass.

--- On Tue, 4/20/10, Richard Porro <> wrote:

From: Richard Porro <>
Subject: Re: [JudoList] judo physics **** question
To: "'Discussion of All Aspects of Traditional and Modern Judo'"
<>
Date: Tuesday, April 20, 2010, 11:19 AM

I am not going to forward this to my dojo. I have nothing but engineers.
Including 2 MIT PhD's try to teach this group of people an art. I have
said,
"throw to the perpendicular of the line that connects to the back of your
feet" so many times I get light headed every time I go to class. I even
started teaching throws as equations. aaaaaaaaaaaaaaHHHHHHHHHHHHHHHH

Richard Porro

If it isn't full contact, it isn't martial arts!
-----Original Message-----
From: judolist- [mailto:judolist-]
On
Behalf Of Jonathan Jeffer
Sent: Monday, April 19, 2010 5:47 PM
To: Judo-L Judo-L
Subject: [JudoList] judo physics **** question

Okay - for the engineers and scientists on the list.
I was thinking about this question -
Its clear that it takes more energy (and greater force) to accelerate a
heavier body than a smaller one. Also to stop heavier body already in
motion. Does anyone know if the relationship of force required to the mass
is linear or exponential? Or - putting it another way as players get
heavier does the force required at the margin go up ?
Jon



_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. There is a really cool older book "The Secrets of Judo" by Jiichi Watanabe. It talks about the physics of judo

-----Original Message-----
From: judolist- [mailto:judolist-] On Behalf Of Richard Porro
Sent: Tuesday, April 20, 2010 12:39 PM
To: 'Discussion of All Aspects of Traditional and Modern Judo'
Subject: Re: [JudoList] judo physics **** question

See, I knew this would happen, it sounds just like my judo class. 3 minutes
of demonstration. 15 minutes of the math behind it.

Richard Porro

If it isn't full contact, it isn't martial arts!

-----Original Message-----
From: judolist- [mailto:judolist-] On
Behalf Of Carl Hayes
Sent: Tuesday, April 20, 2010 11:29 AM
To: Discussion of All Aspects of Traditional and Modern Judo
Subject: Re: [JudoList] judo physics **** question

Do they really accelerate slower? Or do they just have a greater distance
to travel? But maybe they really do accelerate slower, because after all
their mass is proportional to the cube of their height if they are of
similar build -- very nonlinear.

So, for example, if you are 10% taller than I am (and built the same), you
must move 10% farther, and you must move 33% more mass, too. So you'd
better be 44% stronger if you want to move a body length in the same time I
move a body length.

Yeah, I'll bet they accelerate slower.

-- Carl
.
----- Original Message -----
From: Jonathan Jeffer
To: Discussion of All Aspects of Traditional and Modern Judo
Sent: Tuesday, April 20, 2010 12:10 PM
Subject: Re: [JudoList] judo physics **** question


What I was wondering about is something I have observed - that big people
tend to accelerate slower and change direction slower than smaller people.
The energy needed to accelerate more mass is clear. What I was wonder
about was whether it gets harder as mass goes up. What Carl corrected me on
is that its not actually harder, because the relationship is linear. Other
factors might not be linear. Like the ratio of strength to mass.

--- On Tue, 4/20/10, Richard Porro <> wrote:

From: Richard Porro <>
Subject: Re: [JudoList] judo physics **** question
To: "'Discussion of All Aspects of Traditional and Modern Judo'"
<>
Date: Tuesday, April 20, 2010, 11:19 AM

I am not going to forward this to my dojo. I have nothing but engineers.
Including 2 MIT PhD's try to teach this group of people an art. I have
said,
"throw to the perpendicular of the line that connects to the back of your
feet" so many times I get light headed every time I go to class. I even
started teaching throws as equations. aaaaaaaaaaaaaaHHHHHHHHHHHHHHHH

Richard Porro

If it isn't full contact, it isn't martial arts!
-----Original Message-----
From: judolist- [mailto:judolist-]
On
Behalf Of Jonathan Jeffer
Sent: Monday, April 19, 2010 5:47 PM
To: Judo-L Judo-L
Subject: [JudoList] judo physics **** question

Okay - for the engineers and scientists on the list.
I was thinking about this question -
Its clear that it takes more energy (and greater force) to accelerate a
heavier body than a smaller one. Also to stop heavier body already in
motion. Does anyone know if the relationship of force required to the mass
is linear or exponential? Or - putting it another way as players get
heavier does the force required at the margin go up ?
Jon



_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe.

Okay - for the engineers and scientists on the list.
I was thinking about this question -
Its clear that it takes more energy (and greater force) to accelerate a heavier body than a smaller one. Also to stop heavier body already in motion.  Does anyone know if the relationship of force required to the mass is linear or exponential?  Or - putting it another way as players get heavier does the force required at the margin go up ?
Jon



_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. For the same acceleration, the force is proportional to the mass. f=ma is a basic foundation of first-semester physics.

-- Carl
.
----- Original Message -----
From: Jonathan Jeffer
To: Judo-L Judo-L
Sent: Monday, April 19, 2010 6:47 PM
Subject: [JudoList] judo physics **** question


Okay - for the engineers and scientists on the list.
I was thinking about this question -
Its clear that it takes more energy (and greater force) to accelerate a heavier body than a smaller one. Also to stop heavier body already in motion. Does anyone know if the relationship of force required to the mass is linear or exponential? Or - putting it another way as players get heavier does the force required at the margin go up ?
Jon



_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. 1st semester was a long time ago. I know the equation I was just not thinking clearly.  Makes sense.


Subject: Re: [JudoList] judo physics **** question
Date: Monday, April 19, 2010, 6:51 PM

For the same acceleration, the force is proportional to the mass.  f=ma is a basic foundation of first-semester physics.

  -- Carl
.
  ----- Original Message -----
  From: Jonathan Jeffer
  To: Judo-L Judo-L
  Sent: Monday, April 19, 2010 6:47 PM
  Subject: [JudoList] judo physics **** question


  Okay - for the engineers and scientists on the list.
  I was thinking about this question -
  Its clear that it takes more energy (and greater force) to accelerate a heavier body than a smaller one. Also to stop heavier body already in motion. Does anyone know if the relationship of force required to the mass is linear or exponential? Or - putting it another way as players get heavier does the force required at the margin go up ?
  Jon


       
  _______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. I am not going to forward this to my dojo. I have nothing but engineers.
Including 2 MIT PhD's try to teach this group of people an art. I have said,
"throw to the perpendicular of the line that connects to the back of your
feet" so many times I get light headed every time I go to class. I even
started teaching throws as equations. aaaaaaaaaaaaaaHHHHHHHHHHHHHHHH

Richard Porro

If it isn't full contact, it isn't martial arts!
-----Original Message-----
From: judolist- [mailto:judolist-] On
Behalf Of Jonathan Jeffer
Sent: Monday, April 19, 2010 5:47 PM
To: Judo-L Judo-L
Subject: [JudoList] judo physics **** question

Okay - for the engineers and scientists on the list.
I was thinking about this question -
Its clear that it takes more energy (and greater force) to accelerate a
heavier body than a smaller one. Also to stop heavier body already in
motion.  Does anyone know if the relationship of force required to the mass
is linear or exponential?  Or - putting it another way as players get
heavier does the force required at the margin go up ?
Jon



_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. Sounds like Monday night class again.:)

Richard Porro

If it isn't full contact, it isn't martial arts!

-----Original Message-----
From: judolist- [mailto:judolist-] On
Behalf Of Carl Hayes
Sent: Monday, April 19, 2010 5:52 PM
To: Discussion of All Aspects of Traditional and Modern Judo
Subject: Re: [JudoList] judo physics **** question

For the same acceleration, the force is proportional to the mass. f=ma is a
basic foundation of first-semester physics.

-- Carl
.
----- Original Message -----
From: Jonathan Jeffer
To: Judo-L Judo-L
Sent: Monday, April 19, 2010 6:47 PM
Subject: [JudoList] judo physics **** question


Okay - for the engineers and scientists on the list.
I was thinking about this question -
Its clear that it takes more energy (and greater force) to accelerate a
heavier body than a smaller one. Also to stop heavier body already in
motion. Does anyone know if the relationship of force required to the mass
is linear or exponential? Or - putting it another way as players get heavier
does the force required at the margin go up ?
Jon



_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. What I was wondering about is something I have observed - that big people tend to accelerate slower and change direction slower  than smaller people.
The energy needed to accelerate more mass is clear.  What I was wonder about was whether it gets harder as mass goes up.  What Carl corrected me on is that its not actually harder, because the relationship is linear.  Other factors might not be linear.  Like the ratio of strength to mass.

--- On Tue, 4/20/10, Richard Porro <> wrote:

From: Richard Porro <>
Subject: Re: [JudoList] judo physics **** question
To: "'Discussion of All Aspects of Traditional and Modern Judo'" <>
Date: Tuesday, April 20, 2010, 11:19 AM

I am not going to forward this to my dojo. I have nothing but engineers.
Including 2 MIT PhD's try to teach this group of people an art. I have said,
"throw to the perpendicular of the line that connects to the back of your
feet" so many times I get light headed every time I go to class. I even
started teaching throws as equations. aaaaaaaaaaaaaaHHHHHHHHHHHHHHHH

Richard Porro

If it isn't full contact, it isn't martial arts!
-----Original Message-----
From: judolist- [mailto:judolist-] On
Behalf Of Jonathan Jeffer
Sent: Monday, April 19, 2010 5:47 PM
To: Judo-L Judo-L
Subject: [JudoList] judo physics **** question

Okay - for the engineers and scientists on the list.
I was thinking about this question -
Its clear that it takes more energy (and greater force) to accelerate a
heavier body than a smaller one. Also to stop heavier body already in
motion.  Does anyone know if the relationship of force required to the mass
is linear or exponential?  Or - putting it another way as players get
heavier does the force required at the margin go up ?
Jon


     
_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. You are correct. It takes longer for a larger person to arrive at the "sweet" spot of no return as my sensei used to say. Most people try to throw to soon and therefore have to force the engagement.


T Ryan





-----Original Message-----
From: Jonathan Jeffer <>
To: Discussion of All Aspects of Traditional and Modern Judo <>
Sent: Tue, Apr 20, 2010 12:10 pm
Subject: Re: [JudoList] judo physics **** question


What I was wondering about is something I have observed - that big people tend
to accelerate slower and change direction slower than smaller people.
The energy needed to accelerate more mass is clear. What I was wonder about was
whether it gets harder as mass goes up. What Carl corrected me on is that its
not actually harder, because the relationship is linear. Other factors might
not be linear. Like the ratio of strength to mass.

--- On Tue, 4/20/10, Richard Porro <> wrote:

From: Richard Porro <>
Subject: Re: [JudoList] judo physics **** question
To: "'Discussion of All Aspects of Traditional and Modern Judo'"
<>
Date: Tuesday, April 20, 2010, 11:19 AM

I am not going to forward this to my dojo. I have nothing but engineers.
Including 2 MIT PhD's try to teach this group of people an art. I have said,
"throw to the perpendicular of the line that connects to the back of your
feet" so many times I get light headed every time I go to class. I even
started teaching throws as equations. aaaaaaaaaaaaaaHHHHHHHHHHHHHHHH

Richard Porro

If it isn't full contact, it isn't martial arts!
-----Original Message-----
From: judolist- [mailto:judolist-] On
Behalf Of Jonathan Jeffer
Sent: Monday, April 19, 2010 5:47 PM
To: Judo-L Judo-L
Subject: [JudoList] judo physics **** question

Okay - for the engineers and scientists on the list.
I was thinking about this question -
Its clear that it takes more energy (and greater force) to accelerate a
heavier body than a smaller one. Also to stop heavier body already in
motion. Does anyone know if the relationship of force required to the mass
is linear or exponential? Or - putting it another way as players get
heavier does the force required at the margin go up ?
Jon



_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. Do they really accelerate slower? Or do they just have a greater distance to travel? But maybe they really do accelerate slower, because after all their mass is proportional to the cube of their height if they are of similar build -- very nonlinear.

So, for example, if you are 10% taller than I am (and built the same), you must move 10% farther, and you must move 33% more mass, too. So you'd better be 44% stronger if you want to move a body length in the same time I move a body length.

Yeah, I'll bet they accelerate slower.

-- Carl
.
----- Original Message -----
From: Jonathan Jeffer
To: Discussion of All Aspects of Traditional and Modern Judo
Sent: Tuesday, April 20, 2010 12:10 PM
Subject: Re: [JudoList] judo physics **** question


What I was wondering about is something I have observed - that big people tend to accelerate slower and change direction slower than smaller people.
The energy needed to accelerate more mass is clear. What I was wonder about was whether it gets harder as mass goes up. What Carl corrected me on is that its not actually harder, because the relationship is linear. Other factors might not be linear. Like the ratio of strength to mass.

--- On Tue, 4/20/10, Richard Porro <> wrote:

From: Richard Porro <>
Subject: Re: [JudoList] judo physics **** question
To: "'Discussion of All Aspects of Traditional and Modern Judo'" <>
Date: Tuesday, April 20, 2010, 11:19 AM

I am not going to forward this to my dojo. I have nothing but engineers.
Including 2 MIT PhD's try to teach this group of people an art. I have said,
"throw to the perpendicular of the line that connects to the back of your
feet" so many times I get light headed every time I go to class. I even
started teaching throws as equations. aaaaaaaaaaaaaaHHHHHHHHHHHHHHHH

Richard Porro

If it isn't full contact, it isn't martial arts!
-----Original Message-----
From: judolist- [mailto:judolist-] On
Behalf Of Jonathan Jeffer
Sent: Monday, April 19, 2010 5:47 PM
To: Judo-L Judo-L
Subject: [JudoList] judo physics **** question

Okay - for the engineers and scientists on the list.
I was thinking about this question -
Its clear that it takes more energy (and greater force) to accelerate a
heavier body than a smaller one. Also to stop heavier body already in
motion. Does anyone know if the relationship of force required to the mass
is linear or exponential? Or - putting it another way as players get
heavier does the force required at the margin go up ?
Jon



_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. That is true. They don't wait for the off balance and are forced to muscle
thru. Also another observation is that" big people" tend to force things
using brute strength first before they even try to off balance Uke.



Richard Porro



If it isn't full contact, it isn't martial arts!



-----Original Message-----
From: judolist- [mailto:judolist-] On
Behalf Of
Sent: Tuesday, April 20, 2010 11:23 AM
To:
Subject: Re: [JudoList] judo physics **** question



You are correct. It takes longer for a larger person to arrive at the
"sweet" spot of no return as my sensei used to say. Most people try to
throw to soon and therefore have to force the engagement.





T Ryan











-----Original Message-----

From: Jonathan Jeffer <>

To: Discussion of All Aspects of Traditional and Modern Judo
<>

Sent: Tue, Apr 20, 2010 12:10 pm

Subject: Re: [JudoList] judo physics **** question





What I was wondering about is something I have observed - that big people
tend

to accelerate slower and change direction slower than smaller people.

The energy needed to accelerate more mass is clear. What I was wonder about
was

whether it gets harder as mass goes up. What Carl corrected me on is that
its

not actually harder, because the relationship is linear. Other factors
might

not be linear. Like the ratio of strength to mass.



--- On Tue, 4/20/10, Richard Porro <> wrote:



From: Richard Porro <>

Subject: Re: [JudoList] judo physics **** question

To: "'Discussion of All Aspects of Traditional and Modern Judo'"

<>

Date: Tuesday, April 20, 2010, 11:19 AM



I am not going to forward this to my dojo. I have nothing but engineers.

Including 2 MIT PhD's try to teach this group of people an art. I have said,

"throw to the perpendicular of the line that connects to the back of your

feet" so many times I get light headed every time I go to class. I even

started teaching throws as equations. aaaaaaaaaaaaaaHHHHHHHHHHHHHHHH



Richard Porro



If it isn't full contact, it isn't martial arts!

-----Original Message-----

From: judolist- [mailto:judolist-] On

Behalf Of Jonathan Jeffer

Sent: Monday, April 19, 2010 5:47 PM

To: Judo-L Judo-L

Subject: [JudoList] judo physics **** question



Okay - for the engineers and scientists on the list.

I was thinking about this question -

Its clear that it takes more energy (and greater force) to accelerate a

heavier body than a smaller one. Also to stop heavier body already in

motion. Does anyone know if the relationship of force required to the mass

is linear or exponential? Or - putting it another way as players get

heavier does the force required at the margin go up ?

Jon







_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. Now THAT's funny, I don't care who you are...



On Tue, Apr 20, 2010 at 8:19 AM, Richard Porro <> wrote:

> I am not going to forward this to my dojo. I have nothing but engineers.
> Including 2 MIT PhD's try to teach this group of people an art. I have
> said,
> "throw to the perpendicular of the line that connects to the back of your
> feet" so many times I get light headed every time I go to class. I even
> started teaching throws as equations. aaaaaaaaaaaaaaHHHHHHHHHHHHHHHH
>
> Richard Porro
>
> If it isn't full contact, it isn't martial arts!
> -----Original Message-----
> From: judolist- [mailto:judolist-]
> On
> Behalf Of Jonathan Jeffer
> Sent: Monday, April 19, 2010 5:47 PM
> To: Judo-L Judo-L
> Subject: [JudoList] judo physics **** question
>
> Okay - for the engineers and scientists on the list.
> I was thinking about this question -
> Its clear that it takes more energy (and greater force) to accelerate a
> heavier body than a smaller one. Also to stop heavier body already in
> motion. Does anyone know if the relationship of force required to the mass
> is linear or exponential? Or - putting it another way as players get
> heavier does the force required at the margin go up ?
> Jon
>
>
>
> _______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. Acceleration is force divided by mass. Greater mass equals lower acceleration. Newton's 2nd law.

-----Original Message-----
From: judolist- [mailto:judolist-] On Behalf Of Carl Hayes
Sent: Tuesday, April 20, 2010 12:29 PM
To: Discussion of All Aspects of Traditional and Modern Judo
Subject: Re: [JudoList] judo physics **** question

Do they really accelerate slower? Or do they just have a greater distance to travel? But maybe they really do accelerate slower, because after all their mass is proportional to the cube of their height if they are of similar build -- very nonlinear.

So, for example, if you are 10% taller than I am (and built the same), you must move 10% farther, and you must move 33% more mass, too. So you'd better be 44% stronger if you want to move a body length in the same time I move a body length.

Yeah, I'll bet they accelerate slower.

-- Carl
.
----- Original Message -----
From: Jonathan Jeffer
To: Discussion of All Aspects of Traditional and Modern Judo
Sent: Tuesday, April 20, 2010 12:10 PM
Subject: Re: [JudoList] judo physics **** question


What I was wondering about is something I have observed - that big people tend to accelerate slower and change direction slower than smaller people.
The energy needed to accelerate more mass is clear. What I was wonder about was whether it gets harder as mass goes up. What Carl corrected me on is that its not actually harder, because the relationship is linear. Other factors might not be linear. Like the ratio of strength to mass.

--- On Tue, 4/20/10, Richard Porro <> wrote:

From: Richard Porro <>
Subject: Re: [JudoList] judo physics **** question
To: "'Discussion of All Aspects of Traditional and Modern Judo'" <>
Date: Tuesday, April 20, 2010, 11:19 AM

I am not going to forward this to my dojo. I have nothing but engineers.
Including 2 MIT PhD's try to teach this group of people an art. I have said,
"throw to the perpendicular of the line that connects to the back of your
feet" so many times I get light headed every time I go to class. I even
started teaching throws as equations. aaaaaaaaaaaaaaHHHHHHHHHHHHHHHH

Richard Porro

If it isn't full contact, it isn't martial arts!
-----Original Message-----
From: judolist- [mailto:judolist-] On
Behalf Of Jonathan Jeffer
Sent: Monday, April 19, 2010 5:47 PM
To: Judo-L Judo-L
Subject: [JudoList] judo physics **** question

Okay - for the engineers and scientists on the list.
I was thinking about this question -
Its clear that it takes more energy (and greater force) to accelerate a
heavier body than a smaller one. Also to stop heavier body already in
motion. Does anyone know if the relationship of force required to the mass
is linear or exponential? Or - putting it another way as players get
heavier does the force required at the margin go up ?
Jon



_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. See, I knew this would happen, it sounds just like my judo class. 3 minutes
of demonstration. 15 minutes of the math behind it.

Richard Porro

If it isn't full contact, it isn't martial arts!

-----Original Message-----
From: judolist- [mailto:judolist-] On
Behalf Of Carl Hayes
Sent: Tuesday, April 20, 2010 11:29 AM
To: Discussion of All Aspects of Traditional and Modern Judo
Subject: Re: [JudoList] judo physics **** question

Do they really accelerate slower? Or do they just have a greater distance
to travel? But maybe they really do accelerate slower, because after all
their mass is proportional to the cube of their height if they are of
similar build -- very nonlinear.

So, for example, if you are 10% taller than I am (and built the same), you
must move 10% farther, and you must move 33% more mass, too. So you'd
better be 44% stronger if you want to move a body length in the same time I
move a body length.

Yeah, I'll bet they accelerate slower.

-- Carl
.
----- Original Message -----
From: Jonathan Jeffer
To: Discussion of All Aspects of Traditional and Modern Judo
Sent: Tuesday, April 20, 2010 12:10 PM
Subject: Re: [JudoList] judo physics **** question


What I was wondering about is something I have observed - that big people
tend to accelerate slower and change direction slower than smaller people.
The energy needed to accelerate more mass is clear. What I was wonder
about was whether it gets harder as mass goes up. What Carl corrected me on
is that its not actually harder, because the relationship is linear. Other
factors might not be linear. Like the ratio of strength to mass.

--- On Tue, 4/20/10, Richard Porro <> wrote:

From: Richard Porro <>
Subject: Re: [JudoList] judo physics **** question
To: "'Discussion of All Aspects of Traditional and Modern Judo'"
<>
Date: Tuesday, April 20, 2010, 11:19 AM

I am not going to forward this to my dojo. I have nothing but engineers.
Including 2 MIT PhD's try to teach this group of people an art. I have
said,
"throw to the perpendicular of the line that connects to the back of your
feet" so many times I get light headed every time I go to class. I even
started teaching throws as equations. aaaaaaaaaaaaaaHHHHHHHHHHHHHHHH

Richard Porro

If it isn't full contact, it isn't martial arts!
-----Original Message-----
From: judolist- [mailto:judolist-]
On
Behalf Of Jonathan Jeffer
Sent: Monday, April 19, 2010 5:47 PM
To: Judo-L Judo-L
Subject: [JudoList] judo physics **** question

Okay - for the engineers and scientists on the list.
I was thinking about this question -
Its clear that it takes more energy (and greater force) to accelerate a
heavier body than a smaller one. Also to stop heavier body already in
motion. Does anyone know if the relationship of force required to the mass
is linear or exponential? Or - putting it another way as players get
heavier does the force required at the margin go up ?
Jon



_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. There is a really cool older book "The Secrets of Judo" by Jiichi Watanabe. It talks about the physics of judo

-----Original Message-----
From: judolist- [mailto:judolist-] On Behalf Of Richard Porro
Sent: Tuesday, April 20, 2010 12:39 PM
To: 'Discussion of All Aspects of Traditional and Modern Judo'
Subject: Re: [JudoList] judo physics **** question

See, I knew this would happen, it sounds just like my judo class. 3 minutes
of demonstration. 15 minutes of the math behind it.

Richard Porro

If it isn't full contact, it isn't martial arts!

-----Original Message-----
From: judolist- [mailto:judolist-] On
Behalf Of Carl Hayes
Sent: Tuesday, April 20, 2010 11:29 AM
To: Discussion of All Aspects of Traditional and Modern Judo
Subject: Re: [JudoList] judo physics **** question

Do they really accelerate slower? Or do they just have a greater distance
to travel? But maybe they really do accelerate slower, because after all
their mass is proportional to the cube of their height if they are of
similar build -- very nonlinear.

So, for example, if you are 10% taller than I am (and built the same), you
must move 10% farther, and you must move 33% more mass, too. So you'd
better be 44% stronger if you want to move a body length in the same time I
move a body length.

Yeah, I'll bet they accelerate slower.

-- Carl
.
----- Original Message -----
From: Jonathan Jeffer
To: Discussion of All Aspects of Traditional and Modern Judo
Sent: Tuesday, April 20, 2010 12:10 PM
Subject: Re: [JudoList] judo physics **** question


What I was wondering about is something I have observed - that big people
tend to accelerate slower and change direction slower than smaller people.
The energy needed to accelerate more mass is clear. What I was wonder
about was whether it gets harder as mass goes up. What Carl corrected me on
is that its not actually harder, because the relationship is linear. Other
factors might not be linear. Like the ratio of strength to mass.

--- On Tue, 4/20/10, Richard Porro <> wrote:

From: Richard Porro <>
Subject: Re: [JudoList] judo physics **** question
To: "'Discussion of All Aspects of Traditional and Modern Judo'"
<>
Date: Tuesday, April 20, 2010, 11:19 AM

I am not going to forward this to my dojo. I have nothing but engineers.
Including 2 MIT PhD's try to teach this group of people an art. I have
said,
"throw to the perpendicular of the line that connects to the back of your
feet" so many times I get light headed every time I go to class. I even
started teaching throws as equations. aaaaaaaaaaaaaaHHHHHHHHHHHHHHHH

Richard Porro

If it isn't full contact, it isn't martial arts!
-----Original Message-----
From: judolist- [mailto:judolist-]
On
Behalf Of Jonathan Jeffer
Sent: Monday, April 19, 2010 5:47 PM
To: Judo-L Judo-L
Subject: [JudoList] judo physics **** question

Okay - for the engineers and scientists on the list.
I was thinking about this question -
Its clear that it takes more energy (and greater force) to accelerate a
heavier body than a smaller one. Also to stop heavier body already in
motion. Does anyone know if the relationship of force required to the mass
is linear or exponential? Or - putting it another way as players get
heavier does the force required at the margin go up ?
Jon



_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. On Apr 20, 2010, at 9:37 AM, Richard Porro wrote:

> That is true. They don't wait for the off balance and are forced to muscle
> thru. Also another observation is that" big people" tend to force things
> using brute strength first before they even try to off balance Uke.

I think that's too much of a broad generalization. Strength and power are assets. If you have them in ample supply, you would tend to use them, particularly in the absence of other tools. I would offer that your statement is more true with lesser skilled and lesser experienced practitioners. But then... Even the "smaller people" will tend to force things (or "try" to force things) if that's the only option they perceive.

You being a larger person, I think you can totally agree that when you started judo (or karate for that matter), you used a lot more strength and power than you do now that you "know better".


-D. Israel

http://www.customcodebydan.com
AIM: JudoDanIzz

If a dozen smart, successful people who've achieved something great are all giving the same advice, take it.

_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe.

Okay - for the engineers and scientists on the list.
I was thinking about this question -
Its clear that it takes more energy (and greater force) to accelerate a heavier body than a smaller one. Also to stop heavier body already in motion.  Does anyone know if the relationship of force required to the mass is linear or exponential?  Or - putting it another way as players get heavier does the force required at the margin go up ?
Jon



_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. For the same acceleration, the force is proportional to the mass. f=ma is a basic foundation of first-semester physics.

-- Carl
.
----- Original Message -----
From: Jonathan Jeffer
To: Judo-L Judo-L
Sent: Monday, April 19, 2010 6:47 PM
Subject: [JudoList] judo physics **** question


Okay - for the engineers and scientists on the list.
I was thinking about this question -
Its clear that it takes more energy (and greater force) to accelerate a heavier body than a smaller one. Also to stop heavier body already in motion. Does anyone know if the relationship of force required to the mass is linear or exponential? Or - putting it another way as players get heavier does the force required at the margin go up ?
Jon



_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. 1st semester was a long time ago. I know the equation I was just not thinking clearly.  Makes sense.


Subject: Re: [JudoList] judo physics **** question
Date: Monday, April 19, 2010, 6:51 PM

For the same acceleration, the force is proportional to the mass.  f=ma is a basic foundation of first-semester physics.

  -- Carl
.
  ----- Original Message -----
  From: Jonathan Jeffer
  To: Judo-L Judo-L
  Sent: Monday, April 19, 2010 6:47 PM
  Subject: [JudoList] judo physics **** question


  Okay - for the engineers and scientists on the list.
  I was thinking about this question -
  Its clear that it takes more energy (and greater force) to accelerate a heavier body than a smaller one. Also to stop heavier body already in motion. Does anyone know if the relationship of force required to the mass is linear or exponential? Or - putting it another way as players get heavier does the force required at the margin go up ?
  Jon


       
  _______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. I am not going to forward this to my dojo. I have nothing but engineers.
Including 2 MIT PhD's try to teach this group of people an art. I have said,
"throw to the perpendicular of the line that connects to the back of your
feet" so many times I get light headed every time I go to class. I even
started teaching throws as equations. aaaaaaaaaaaaaaHHHHHHHHHHHHHHHH

Richard Porro

If it isn't full contact, it isn't martial arts!
-----Original Message-----
From: judolist- [mailto:judolist-] On
Behalf Of Jonathan Jeffer
Sent: Monday, April 19, 2010 5:47 PM
To: Judo-L Judo-L
Subject: [JudoList] judo physics **** question

Okay - for the engineers and scientists on the list.
I was thinking about this question -
Its clear that it takes more energy (and greater force) to accelerate a
heavier body than a smaller one. Also to stop heavier body already in
motion.  Does anyone know if the relationship of force required to the mass
is linear or exponential?  Or - putting it another way as players get
heavier does the force required at the margin go up ?
Jon



_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. Sounds like Monday night class again.:)

Richard Porro

If it isn't full contact, it isn't martial arts!

-----Original Message-----
From: judolist- [mailto:judolist-] On
Behalf Of Carl Hayes
Sent: Monday, April 19, 2010 5:52 PM
To: Discussion of All Aspects of Traditional and Modern Judo
Subject: Re: [JudoList] judo physics **** question

For the same acceleration, the force is proportional to the mass. f=ma is a
basic foundation of first-semester physics.

-- Carl
.
----- Original Message -----
From: Jonathan Jeffer
To: Judo-L Judo-L
Sent: Monday, April 19, 2010 6:47 PM
Subject: [JudoList] judo physics **** question


Okay - for the engineers and scientists on the list.
I was thinking about this question -
Its clear that it takes more energy (and greater force) to accelerate a
heavier body than a smaller one. Also to stop heavier body already in
motion. Does anyone know if the relationship of force required to the mass
is linear or exponential? Or - putting it another way as players get heavier
does the force required at the margin go up ?
Jon



_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. What I was wondering about is something I have observed - that big people tend to accelerate slower and change direction slower  than smaller people.
The energy needed to accelerate more mass is clear.  What I was wonder about was whether it gets harder as mass goes up.  What Carl corrected me on is that its not actually harder, because the relationship is linear.  Other factors might not be linear.  Like the ratio of strength to mass.

--- On Tue, 4/20/10, Richard Porro <> wrote:

From: Richard Porro <>
Subject: Re: [JudoList] judo physics **** question
To: "'Discussion of All Aspects of Traditional and Modern Judo'" <>
Date: Tuesday, April 20, 2010, 11:19 AM

I am not going to forward this to my dojo. I have nothing but engineers.
Including 2 MIT PhD's try to teach this group of people an art. I have said,
"throw to the perpendicular of the line that connects to the back of your
feet" so many times I get light headed every time I go to class. I even
started teaching throws as equations. aaaaaaaaaaaaaaHHHHHHHHHHHHHHHH

Richard Porro

If it isn't full contact, it isn't martial arts!
-----Original Message-----
From: judolist- [mailto:judolist-] On
Behalf Of Jonathan Jeffer
Sent: Monday, April 19, 2010 5:47 PM
To: Judo-L Judo-L
Subject: [JudoList] judo physics **** question

Okay - for the engineers and scientists on the list.
I was thinking about this question -
Its clear that it takes more energy (and greater force) to accelerate a
heavier body than a smaller one. Also to stop heavier body already in
motion.  Does anyone know if the relationship of force required to the mass
is linear or exponential?  Or - putting it another way as players get
heavier does the force required at the margin go up ?
Jon


     
_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. You are correct. It takes longer for a larger person to arrive at the "sweet" spot of no return as my sensei used to say. Most people try to throw to soon and therefore have to force the engagement.


T Ryan





-----Original Message-----
From: Jonathan Jeffer <>
To: Discussion of All Aspects of Traditional and Modern Judo <>
Sent: Tue, Apr 20, 2010 12:10 pm
Subject: Re: [JudoList] judo physics **** question


What I was wondering about is something I have observed - that big people tend
to accelerate slower and change direction slower than smaller people.
The energy needed to accelerate more mass is clear. What I was wonder about was
whether it gets harder as mass goes up. What Carl corrected me on is that its
not actually harder, because the relationship is linear. Other factors might
not be linear. Like the ratio of strength to mass.

--- On Tue, 4/20/10, Richard Porro <> wrote:

From: Richard Porro <>
Subject: Re: [JudoList] judo physics **** question
To: "'Discussion of All Aspects of Traditional and Modern Judo'"
<>
Date: Tuesday, April 20, 2010, 11:19 AM

I am not going to forward this to my dojo. I have nothing but engineers.
Including 2 MIT PhD's try to teach this group of people an art. I have said,
"throw to the perpendicular of the line that connects to the back of your
feet" so many times I get light headed every time I go to class. I even
started teaching throws as equations. aaaaaaaaaaaaaaHHHHHHHHHHHHHHHH

Richard Porro

If it isn't full contact, it isn't martial arts!
-----Original Message-----
From: judolist- [mailto:judolist-] On
Behalf Of Jonathan Jeffer
Sent: Monday, April 19, 2010 5:47 PM
To: Judo-L Judo-L
Subject: [JudoList] judo physics **** question

Okay - for the engineers and scientists on the list.
I was thinking about this question -
Its clear that it takes more energy (and greater force) to accelerate a
heavier body than a smaller one. Also to stop heavier body already in
motion. Does anyone know if the relationship of force required to the mass
is linear or exponential? Or - putting it another way as players get
heavier does the force required at the margin go up ?
Jon



_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. Do they really accelerate slower? Or do they just have a greater distance to travel? But maybe they really do accelerate slower, because after all their mass is proportional to the cube of their height if they are of similar build -- very nonlinear.

So, for example, if you are 10% taller than I am (and built the same), you must move 10% farther, and you must move 33% more mass, too. So you'd better be 44% stronger if you want to move a body length in the same time I move a body length.

Yeah, I'll bet they accelerate slower.

-- Carl
.
----- Original Message -----
From: Jonathan Jeffer
To: Discussion of All Aspects of Traditional and Modern Judo
Sent: Tuesday, April 20, 2010 12:10 PM
Subject: Re: [JudoList] judo physics **** question


What I was wondering about is something I have observed - that big people tend to accelerate slower and change direction slower than smaller people.
The energy needed to accelerate more mass is clear. What I was wonder about was whether it gets harder as mass goes up. What Carl corrected me on is that its not actually harder, because the relationship is linear. Other factors might not be linear. Like the ratio of strength to mass.

--- On Tue, 4/20/10, Richard Porro <> wrote:

From: Richard Porro <>
Subject: Re: [JudoList] judo physics **** question
To: "'Discussion of All Aspects of Traditional and Modern Judo'" <>
Date: Tuesday, April 20, 2010, 11:19 AM

I am not going to forward this to my dojo. I have nothing but engineers.
Including 2 MIT PhD's try to teach this group of people an art. I have said,
"throw to the perpendicular of the line that connects to the back of your
feet" so many times I get light headed every time I go to class. I even
started teaching throws as equations. aaaaaaaaaaaaaaHHHHHHHHHHHHHHHH

Richard Porro

If it isn't full contact, it isn't martial arts!
-----Original Message-----
From: judolist- [mailto:judolist-] On
Behalf Of Jonathan Jeffer
Sent: Monday, April 19, 2010 5:47 PM
To: Judo-L Judo-L
Subject: [JudoList] judo physics **** question

Okay - for the engineers and scientists on the list.
I was thinking about this question -
Its clear that it takes more energy (and greater force) to accelerate a
heavier body than a smaller one. Also to stop heavier body already in
motion. Does anyone know if the relationship of force required to the mass
is linear or exponential? Or - putting it another way as players get
heavier does the force required at the margin go up ?
Jon



_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. That is true. They don't wait for the off balance and are forced to muscle
thru. Also another observation is that" big people" tend to force things
using brute strength first before they even try to off balance Uke.



Richard Porro



If it isn't full contact, it isn't martial arts!



-----Original Message-----
From: judolist- [mailto:judolist-] On
Behalf Of
Sent: Tuesday, April 20, 2010 11:23 AM
To:
Subject: Re: [JudoList] judo physics **** question



You are correct. It takes longer for a larger person to arrive at the
"sweet" spot of no return as my sensei used to say. Most people try to
throw to soon and therefore have to force the engagement.





T Ryan











-----Original Message-----

From: Jonathan Jeffer <>

To: Discussion of All Aspects of Traditional and Modern Judo
<>

Sent: Tue, Apr 20, 2010 12:10 pm

Subject: Re: [JudoList] judo physics **** question





What I was wondering about is something I have observed - that big people
tend

to accelerate slower and change direction slower than smaller people.

The energy needed to accelerate more mass is clear. What I was wonder about
was

whether it gets harder as mass goes up. What Carl corrected me on is that
its

not actually harder, because the relationship is linear. Other factors
might

not be linear. Like the ratio of strength to mass.



--- On Tue, 4/20/10, Richard Porro <> wrote:



From: Richard Porro <>

Subject: Re: [JudoList] judo physics **** question

To: "'Discussion of All Aspects of Traditional and Modern Judo'"

<>

Date: Tuesday, April 20, 2010, 11:19 AM



I am not going to forward this to my dojo. I have nothing but engineers.

Including 2 MIT PhD's try to teach this group of people an art. I have said,

"throw to the perpendicular of the line that connects to the back of your

feet" so many times I get light headed every time I go to class. I even

started teaching throws as equations. aaaaaaaaaaaaaaHHHHHHHHHHHHHHHH



Richard Porro



If it isn't full contact, it isn't martial arts!

-----Original Message-----

From: judolist- [mailto:judolist-] On

Behalf Of Jonathan Jeffer

Sent: Monday, April 19, 2010 5:47 PM

To: Judo-L Judo-L

Subject: [JudoList] judo physics **** question



Okay - for the engineers and scientists on the list.

I was thinking about this question -

Its clear that it takes more energy (and greater force) to accelerate a

heavier body than a smaller one. Also to stop heavier body already in

motion. Does anyone know if the relationship of force required to the mass

is linear or exponential? Or - putting it another way as players get

heavier does the force required at the margin go up ?

Jon







_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. Now THAT's funny, I don't care who you are...



On Tue, Apr 20, 2010 at 8:19 AM, Richard Porro <> wrote:

> I am not going to forward this to my dojo. I have nothing but engineers.
> Including 2 MIT PhD's try to teach this group of people an art. I have
> said,
> "throw to the perpendicular of the line that connects to the back of your
> feet" so many times I get light headed every time I go to class. I even
> started teaching throws as equations. aaaaaaaaaaaaaaHHHHHHHHHHHHHHHH
>
> Richard Porro
>
> If it isn't full contact, it isn't martial arts!
> -----Original Message-----
> From: judolist- [mailto:judolist-]
> On
> Behalf Of Jonathan Jeffer
> Sent: Monday, April 19, 2010 5:47 PM
> To: Judo-L Judo-L
> Subject: [JudoList] judo physics **** question
>
> Okay - for the engineers and scientists on the list.
> I was thinking about this question -
> Its clear that it takes more energy (and greater force) to accelerate a
> heavier body than a smaller one. Also to stop heavier body already in
> motion. Does anyone know if the relationship of force required to the mass
> is linear or exponential? Or - putting it another way as players get
> heavier does the force required at the margin go up ?
> Jon
>
>
>
> _______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. Acceleration is force divided by mass. Greater mass equals lower acceleration. Newton's 2nd law.

-----Original Message-----
From: judolist- [mailto:judolist-] On Behalf Of Carl Hayes
Sent: Tuesday, April 20, 2010 12:29 PM
To: Discussion of All Aspects of Traditional and Modern Judo
Subject: Re: [JudoList] judo physics **** question

Do they really accelerate slower? Or do they just have a greater distance to travel? But maybe they really do accelerate slower, because after all their mass is proportional to the cube of their height if they are of similar build -- very nonlinear.

So, for example, if you are 10% taller than I am (and built the same), you must move 10% farther, and you must move 33% more mass, too. So you'd better be 44% stronger if you want to move a body length in the same time I move a body length.

Yeah, I'll bet they accelerate slower.

-- Carl
.
----- Original Message -----
From: Jonathan Jeffer
To: Discussion of All Aspects of Traditional and Modern Judo
Sent: Tuesday, April 20, 2010 12:10 PM
Subject: Re: [JudoList] judo physics **** question


What I was wondering about is something I have observed - that big people tend to accelerate slower and change direction slower than smaller people.
The energy needed to accelerate more mass is clear. What I was wonder about was whether it gets harder as mass goes up. What Carl corrected me on is that its not actually harder, because the relationship is linear. Other factors might not be linear. Like the ratio of strength to mass.

--- On Tue, 4/20/10, Richard Porro <> wrote:

From: Richard Porro <>
Subject: Re: [JudoList] judo physics **** question
To: "'Discussion of All Aspects of Traditional and Modern Judo'" <>
Date: Tuesday, April 20, 2010, 11:19 AM

I am not going to forward this to my dojo. I have nothing but engineers.
Including 2 MIT PhD's try to teach this group of people an art. I have said,
"throw to the perpendicular of the line that connects to the back of your
feet" so many times I get light headed every time I go to class. I even
started teaching throws as equations. aaaaaaaaaaaaaaHHHHHHHHHHHHHHHH

Richard Porro

If it isn't full contact, it isn't martial arts!
-----Original Message-----
From: judolist- [mailto:judolist-] On
Behalf Of Jonathan Jeffer
Sent: Monday, April 19, 2010 5:47 PM
To: Judo-L Judo-L
Subject: [JudoList] judo physics **** question

Okay - for the engineers and scientists on the list.
I was thinking about this question -
Its clear that it takes more energy (and greater force) to accelerate a
heavier body than a smaller one. Also to stop heavier body already in
motion. Does anyone know if the relationship of force required to the mass
is linear or exponential? Or - putting it another way as players get
heavier does the force required at the margin go up ?
Jon



_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. See, I knew this would happen, it sounds just like my judo class. 3 minutes
of demonstration. 15 minutes of the math behind it.

Richard Porro

If it isn't full contact, it isn't martial arts!

-----Original Message-----
From: judolist- [mailto:judolist-] On
Behalf Of Carl Hayes
Sent: Tuesday, April 20, 2010 11:29 AM
To: Discussion of All Aspects of Traditional and Modern Judo
Subject: Re: [JudoList] judo physics **** question

Do they really accelerate slower? Or do they just have a greater distance
to travel? But maybe they really do accelerate slower, because after all
their mass is proportional to the cube of their height if they are of
similar build -- very nonlinear.

So, for example, if you are 10% taller than I am (and built the same), you
must move 10% farther, and you must move 33% more mass, too. So you'd
better be 44% stronger if you want to move a body length in the same time I
move a body length.

Yeah, I'll bet they accelerate slower.

-- Carl
.
----- Original Message -----
From: Jonathan Jeffer
To: Discussion of All Aspects of Traditional and Modern Judo
Sent: Tuesday, April 20, 2010 12:10 PM
Subject: Re: [JudoList] judo physics **** question


What I was wondering about is something I have observed - that big people
tend to accelerate slower and change direction slower than smaller people.
The energy needed to accelerate more mass is clear. What I was wonder
about was whether it gets harder as mass goes up. What Carl corrected me on
is that its not actually harder, because the relationship is linear. Other
factors might not be linear. Like the ratio of strength to mass.

--- On Tue, 4/20/10, Richard Porro <> wrote:

From: Richard Porro <>
Subject: Re: [JudoList] judo physics **** question
To: "'Discussion of All Aspects of Traditional and Modern Judo'"
<>
Date: Tuesday, April 20, 2010, 11:19 AM

I am not going to forward this to my dojo. I have nothing but engineers.
Including 2 MIT PhD's try to teach this group of people an art. I have
said,
"throw to the perpendicular of the line that connects to the back of your
feet" so many times I get light headed every time I go to class. I even
started teaching throws as equations. aaaaaaaaaaaaaaHHHHHHHHHHHHHHHH

Richard Porro

If it isn't full contact, it isn't martial arts!
-----Original Message-----
From: judolist- [mailto:judolist-]
On
Behalf Of Jonathan Jeffer
Sent: Monday, April 19, 2010 5:47 PM
To: Judo-L Judo-L
Subject: [JudoList] judo physics **** question

Okay - for the engineers and scientists on the list.
I was thinking about this question -
Its clear that it takes more energy (and greater force) to accelerate a
heavier body than a smaller one. Also to stop heavier body already in
motion. Does anyone know if the relationship of force required to the mass
is linear or exponential? Or - putting it another way as players get
heavier does the force required at the margin go up ?
Jon



_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. There is a really cool older book "The Secrets of Judo" by Jiichi Watanabe. It talks about the physics of judo

-----Original Message-----
From: judolist- [mailto:judolist-] On Behalf Of Richard Porro
Sent: Tuesday, April 20, 2010 12:39 PM
To: 'Discussion of All Aspects of Traditional and Modern Judo'
Subject: Re: [JudoList] judo physics **** question

See, I knew this would happen, it sounds just like my judo class. 3 minutes
of demonstration. 15 minutes of the math behind it.

Richard Porro

If it isn't full contact, it isn't martial arts!

-----Original Message-----
From: judolist- [mailto:judolist-] On
Behalf Of Carl Hayes
Sent: Tuesday, April 20, 2010 11:29 AM
To: Discussion of All Aspects of Traditional and Modern Judo
Subject: Re: [JudoList] judo physics **** question

Do they really accelerate slower? Or do they just have a greater distance
to travel? But maybe they really do accelerate slower, because after all
their mass is proportional to the cube of their height if they are of
similar build -- very nonlinear.

So, for example, if you are 10% taller than I am (and built the same), you
must move 10% farther, and you must move 33% more mass, too. So you'd
better be 44% stronger if you want to move a body length in the same time I
move a body length.

Yeah, I'll bet they accelerate slower.

-- Carl
.
----- Original Message -----
From: Jonathan Jeffer
To: Discussion of All Aspects of Traditional and Modern Judo
Sent: Tuesday, April 20, 2010 12:10 PM
Subject: Re: [JudoList] judo physics **** question


What I was wondering about is something I have observed - that big people
tend to accelerate slower and change direction slower than smaller people.
The energy needed to accelerate more mass is clear. What I was wonder
about was whether it gets harder as mass goes up. What Carl corrected me on
is that its not actually harder, because the relationship is linear. Other
factors might not be linear. Like the ratio of strength to mass.

--- On Tue, 4/20/10, Richard Porro <> wrote:

From: Richard Porro <>
Subject: Re: [JudoList] judo physics **** question
To: "'Discussion of All Aspects of Traditional and Modern Judo'"
<>
Date: Tuesday, April 20, 2010, 11:19 AM

I am not going to forward this to my dojo. I have nothing but engineers.
Including 2 MIT PhD's try to teach this group of people an art. I have
said,
"throw to the perpendicular of the line that connects to the back of your
feet" so many times I get light headed every time I go to class. I even
started teaching throws as equations. aaaaaaaaaaaaaaHHHHHHHHHHHHHHHH

Richard Porro

If it isn't full contact, it isn't martial arts!
-----Original Message-----
From: judolist- [mailto:judolist-]
On
Behalf Of Jonathan Jeffer
Sent: Monday, April 19, 2010 5:47 PM
To: Judo-L Judo-L
Subject: [JudoList] judo physics **** question

Okay - for the engineers and scientists on the list.
I was thinking about this question -
Its clear that it takes more energy (and greater force) to accelerate a
heavier body than a smaller one. Also to stop heavier body already in
motion. Does anyone know if the relationship of force required to the mass
is linear or exponential? Or - putting it another way as players get
heavier does the force required at the margin go up ?
Jon



_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. On Apr 20, 2010, at 9:37 AM, Richard Porro wrote:

> That is true. They don't wait for the off balance and are forced to muscle
> thru. Also another observation is that" big people" tend to force things
> using brute strength first before they even try to off balance Uke.

I think that's too much of a broad generalization. Strength and power are assets. If you have them in ample supply, you would tend to use them, particularly in the absence of other tools. I would offer that your statement is more true with lesser skilled and lesser experienced practitioners. But then... Even the "smaller people" will tend to force things (or "try" to force things) if that's the only option they perceive.

You being a larger person, I think you can totally agree that when you started judo (or karate for that matter), you used a lot more strength and power than you do now that you "know better".


-D. Israel

http://www.customcodebydan.com
AIM: JudoDanIzz

If a dozen smart, successful people who've achieved something great are all giving the same advice, take it.

_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. We can only use general statements when we have such a large group as well
as diverse one. But I agree with you on both your statements

Richard Porro

If it isn't full contact, it isn't martial arts!

-----Original Message-----
From: judolist- [mailto:judolist-] On
Behalf Of Daniel Israel
Sent: Tuesday, April 20, 2010 11:57 AM
To: Discussion of All Aspects of Traditional and Modern Judo
Subject: Re: [JudoList] judo physics **** question


On Apr 20, 2010, at 9:37 AM, Richard Porro wrote:

> That is true. They don't wait for the off balance and are forced to muscle
> thru. Also another observation is that" big people" tend to force things
> using brute strength first before they even try to off balance Uke.

I think that's too much of a broad generalization. Strength and power are
assets. If you have them in ample supply, you would tend to use them,
particularly in the absence of other tools. I would offer that your
statement is more true with lesser skilled and lesser experienced
practitioners. But then... Even the "smaller people" will tend to force
things (or "try" to force things) if that's the only option they perceive.

You being a larger person, I think you can totally agree that when you
started judo (or karate for that matter), you used a lot more strength and
power than you do now that you "know better".


-D. Israel

http://www.customcodebydan.com
AIM: JudoDanIzz

If a dozen smart, successful people who've achieved something great are all
giving the same advice, take it.

_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe.

Okay - for the engineers and scientists on the list.
I was thinking about this question -
Its clear that it takes more energy (and greater force) to accelerate a heavier body than a smaller one. Also to stop heavier body already in motion.  Does anyone know if the relationship of force required to the mass is linear or exponential?  Or - putting it another way as players get heavier does the force required at the margin go up ?
Jon



_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. For the same acceleration, the force is proportional to the mass. f=ma is a basic foundation of first-semester physics.

-- Carl
.
----- Original Message -----
From: Jonathan Jeffer
To: Judo-L Judo-L
Sent: Monday, April 19, 2010 6:47 PM
Subject: [JudoList] judo physics **** question


Okay - for the engineers and scientists on the list.
I was thinking about this question -
Its clear that it takes more energy (and greater force) to accelerate a heavier body than a smaller one. Also to stop heavier body already in motion. Does anyone know if the relationship of force required to the mass is linear or exponential? Or - putting it another way as players get heavier does the force required at the margin go up ?
Jon



_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. 1st semester was a long time ago. I know the equation I was just not thinking clearly.  Makes sense.


Subject: Re: [JudoList] judo physics **** question
Date: Monday, April 19, 2010, 6:51 PM

For the same acceleration, the force is proportional to the mass.  f=ma is a basic foundation of first-semester physics.

  -- Carl
.
  ----- Original Message -----
  From: Jonathan Jeffer
  To: Judo-L Judo-L
  Sent: Monday, April 19, 2010 6:47 PM
  Subject: [JudoList] judo physics **** question


  Okay - for the engineers and scientists on the list.
  I was thinking about this question -
  Its clear that it takes more energy (and greater force) to accelerate a heavier body than a smaller one. Also to stop heavier body already in motion. Does anyone know if the relationship of force required to the mass is linear or exponential? Or - putting it another way as players get heavier does the force required at the margin go up ?
  Jon


       
  _______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. I am not going to forward this to my dojo. I have nothing but engineers.
Including 2 MIT PhD's try to teach this group of people an art. I have said,
"throw to the perpendicular of the line that connects to the back of your
feet" so many times I get light headed every time I go to class. I even
started teaching throws as equations. aaaaaaaaaaaaaaHHHHHHHHHHHHHHHH

Richard Porro

If it isn't full contact, it isn't martial arts!
-----Original Message-----
From: judolist- [mailto:judolist-] On
Behalf Of Jonathan Jeffer
Sent: Monday, April 19, 2010 5:47 PM
To: Judo-L Judo-L
Subject: [JudoList] judo physics **** question

Okay - for the engineers and scientists on the list.
I was thinking about this question -
Its clear that it takes more energy (and greater force) to accelerate a
heavier body than a smaller one. Also to stop heavier body already in
motion.  Does anyone know if the relationship of force required to the mass
is linear or exponential?  Or - putting it another way as players get
heavier does the force required at the margin go up ?
Jon



_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. Sounds like Monday night class again.:)

Richard Porro

If it isn't full contact, it isn't martial arts!

-----Original Message-----
From: judolist- [mailto:judolist-] On
Behalf Of Carl Hayes
Sent: Monday, April 19, 2010 5:52 PM
To: Discussion of All Aspects of Traditional and Modern Judo
Subject: Re: [JudoList] judo physics **** question

For the same acceleration, the force is proportional to the mass. f=ma is a
basic foundation of first-semester physics.

-- Carl
.
----- Original Message -----
From: Jonathan Jeffer
To: Judo-L Judo-L
Sent: Monday, April 19, 2010 6:47 PM
Subject: [JudoList] judo physics **** question


Okay - for the engineers and scientists on the list.
I was thinking about this question -
Its clear that it takes more energy (and greater force) to accelerate a
heavier body than a smaller one. Also to stop heavier body already in
motion. Does anyone know if the relationship of force required to the mass
is linear or exponential? Or - putting it another way as players get heavier
does the force required at the margin go up ?
Jon



_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. What I was wondering about is something I have observed - that big people tend to accelerate slower and change direction slower  than smaller people.
The energy needed to accelerate more mass is clear.  What I was wonder about was whether it gets harder as mass goes up.  What Carl corrected me on is that its not actually harder, because the relationship is linear.  Other factors might not be linear.  Like the ratio of strength to mass.

--- On Tue, 4/20/10, Richard Porro <> wrote:

From: Richard Porro <>
Subject: Re: [JudoList] judo physics **** question
To: "'Discussion of All Aspects of Traditional and Modern Judo'" <>
Date: Tuesday, April 20, 2010, 11:19 AM

I am not going to forward this to my dojo. I have nothing but engineers.
Including 2 MIT PhD's try to teach this group of people an art. I have said,
"throw to the perpendicular of the line that connects to the back of your
feet" so many times I get light headed every time I go to class. I even
started teaching throws as equations. aaaaaaaaaaaaaaHHHHHHHHHHHHHHHH

Richard Porro

If it isn't full contact, it isn't martial arts!
-----Original Message-----
From: judolist- [mailto:judolist-] On
Behalf Of Jonathan Jeffer
Sent: Monday, April 19, 2010 5:47 PM
To: Judo-L Judo-L
Subject: [JudoList] judo physics **** question

Okay - for the engineers and scientists on the list.
I was thinking about this question -
Its clear that it takes more energy (and greater force) to accelerate a
heavier body than a smaller one. Also to stop heavier body already in
motion.  Does anyone know if the relationship of force required to the mass
is linear or exponential?  Or - putting it another way as players get
heavier does the force required at the margin go up ?
Jon


     
_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. You are correct. It takes longer for a larger person to arrive at the "sweet" spot of no return as my sensei used to say. Most people try to throw to soon and therefore have to force the engagement.


T Ryan





-----Original Message-----
From: Jonathan Jeffer <>
To: Discussion of All Aspects of Traditional and Modern Judo <>
Sent: Tue, Apr 20, 2010 12:10 pm
Subject: Re: [JudoList] judo physics **** question


What I was wondering about is something I have observed - that big people tend
to accelerate slower and change direction slower than smaller people.
The energy needed to accelerate more mass is clear. What I was wonder about was
whether it gets harder as mass goes up. What Carl corrected me on is that its
not actually harder, because the relationship is linear. Other factors might
not be linear. Like the ratio of strength to mass.

--- On Tue, 4/20/10, Richard Porro <> wrote:

From: Richard Porro <>
Subject: Re: [JudoList] judo physics **** question
To: "'Discussion of All Aspects of Traditional and Modern Judo'"
<>
Date: Tuesday, April 20, 2010, 11:19 AM

I am not going to forward this to my dojo. I have nothing but engineers.
Including 2 MIT PhD's try to teach this group of people an art. I have said,
"throw to the perpendicular of the line that connects to the back of your
feet" so many times I get light headed every time I go to class. I even
started teaching throws as equations. aaaaaaaaaaaaaaHHHHHHHHHHHHHHHH

Richard Porro

If it isn't full contact, it isn't martial arts!
-----Original Message-----
From: judolist- [mailto:judolist-] On
Behalf Of Jonathan Jeffer
Sent: Monday, April 19, 2010 5:47 PM
To: Judo-L Judo-L
Subject: [JudoList] judo physics **** question

Okay - for the engineers and scientists on the list.
I was thinking about this question -
Its clear that it takes more energy (and greater force) to accelerate a
heavier body than a smaller one. Also to stop heavier body already in
motion. Does anyone know if the relationship of force required to the mass
is linear or exponential? Or - putting it another way as players get
heavier does the force required at the margin go up ?
Jon



_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. Do they really accelerate slower? Or do they just have a greater distance to travel? But maybe they really do accelerate slower, because after all their mass is proportional to the cube of their height if they are of similar build -- very nonlinear.

So, for example, if you are 10% taller than I am (and built the same), you must move 10% farther, and you must move 33% more mass, too. So you'd better be 44% stronger if you want to move a body length in the same time I move a body length.

Yeah, I'll bet they accelerate slower.

-- Carl
.
----- Original Message -----
From: Jonathan Jeffer
To: Discussion of All Aspects of Traditional and Modern Judo
Sent: Tuesday, April 20, 2010 12:10 PM
Subject: Re: [JudoList] judo physics **** question


What I was wondering about is something I have observed - that big people tend to accelerate slower and change direction slower than smaller people.
The energy needed to accelerate more mass is clear. What I was wonder about was whether it gets harder as mass goes up. What Carl corrected me on is that its not actually harder, because the relationship is linear. Other factors might not be linear. Like the ratio of strength to mass.

--- On Tue, 4/20/10, Richard Porro <> wrote:

From: Richard Porro <>
Subject: Re: [JudoList] judo physics **** question
To: "'Discussion of All Aspects of Traditional and Modern Judo'" <>
Date: Tuesday, April 20, 2010, 11:19 AM

I am not going to forward this to my dojo. I have nothing but engineers.
Including 2 MIT PhD's try to teach this group of people an art. I have said,
"throw to the perpendicular of the line that connects to the back of your
feet" so many times I get light headed every time I go to class. I even
started teaching throws as equations. aaaaaaaaaaaaaaHHHHHHHHHHHHHHHH

Richard Porro

If it isn't full contact, it isn't martial arts!
-----Original Message-----
From: judolist- [mailto:judolist-] On
Behalf Of Jonathan Jeffer
Sent: Monday, April 19, 2010 5:47 PM
To: Judo-L Judo-L
Subject: [JudoList] judo physics **** question

Okay - for the engineers and scientists on the list.
I was thinking about this question -
Its clear that it takes more energy (and greater force) to accelerate a
heavier body than a smaller one. Also to stop heavier body already in
motion. Does anyone know if the relationship of force required to the mass
is linear or exponential? Or - putting it another way as players get
heavier does the force required at the margin go up ?
Jon



_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. That is true. They don't wait for the off balance and are forced to muscle
thru. Also another observation is that" big people" tend to force things
using brute strength first before they even try to off balance Uke.



Richard Porro



If it isn't full contact, it isn't martial arts!



-----Original Message-----
From: judolist- [mailto:judolist-] On
Behalf Of
Sent: Tuesday, April 20, 2010 11:23 AM
To:
Subject: Re: [JudoList] judo physics **** question



You are correct. It takes longer for a larger person to arrive at the
"sweet" spot of no return as my sensei used to say. Most people try to
throw to soon and therefore have to force the engagement.





T Ryan











-----Original Message-----

From: Jonathan Jeffer <>

To: Discussion of All Aspects of Traditional and Modern Judo
<>

Sent: Tue, Apr 20, 2010 12:10 pm

Subject: Re: [JudoList] judo physics **** question





What I was wondering about is something I have observed - that big people
tend

to accelerate slower and change direction slower than smaller people.

The energy needed to accelerate more mass is clear. What I was wonder about
was

whether it gets harder as mass goes up. What Carl corrected me on is that
its

not actually harder, because the relationship is linear. Other factors
might

not be linear. Like the ratio of strength to mass.



--- On Tue, 4/20/10, Richard Porro <> wrote:



From: Richard Porro <>

Subject: Re: [JudoList] judo physics **** question

To: "'Discussion of All Aspects of Traditional and Modern Judo'"

<>

Date: Tuesday, April 20, 2010, 11:19 AM



I am not going to forward this to my dojo. I have nothing but engineers.

Including 2 MIT PhD's try to teach this group of people an art. I have said,

"throw to the perpendicular of the line that connects to the back of your

feet" so many times I get light headed every time I go to class. I even

started teaching throws as equations. aaaaaaaaaaaaaaHHHHHHHHHHHHHHHH



Richard Porro



If it isn't full contact, it isn't martial arts!

-----Original Message-----

From: judolist- [mailto:judolist-] On

Behalf Of Jonathan Jeffer

Sent: Monday, April 19, 2010 5:47 PM

To: Judo-L Judo-L

Subject: [JudoList] judo physics **** question



Okay - for the engineers and scientists on the list.

I was thinking about this question -

Its clear that it takes more energy (and greater force) to accelerate a

heavier body than a smaller one. Also to stop heavier body already in

motion. Does anyone know if the relationship of force required to the mass

is linear or exponential? Or - putting it another way as players get

heavier does the force required at the margin go up ?

Jon







_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. Now THAT's funny, I don't care who you are...



On Tue, Apr 20, 2010 at 8:19 AM, Richard Porro <> wrote:

> I am not going to forward this to my dojo. I have nothing but engineers.
> Including 2 MIT PhD's try to teach this group of people an art. I have
> said,
> "throw to the perpendicular of the line that connects to the back of your
> feet" so many times I get light headed every time I go to class. I even
> started teaching throws as equations. aaaaaaaaaaaaaaHHHHHHHHHHHHHHHH
>
> Richard Porro
>
> If it isn't full contact, it isn't martial arts!
> -----Original Message-----
> From: judolist- [mailto:judolist-]
> On
> Behalf Of Jonathan Jeffer
> Sent: Monday, April 19, 2010 5:47 PM
> To: Judo-L Judo-L
> Subject: [JudoList] judo physics **** question
>
> Okay - for the engineers and scientists on the list.
> I was thinking about this question -
> Its clear that it takes more energy (and greater force) to accelerate a
> heavier body than a smaller one. Also to stop heavier body already in
> motion. Does anyone know if the relationship of force required to the mass
> is linear or exponential? Or - putting it another way as players get
> heavier does the force required at the margin go up ?
> Jon
>
>
>
> _______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. Acceleration is force divided by mass. Greater mass equals lower acceleration. Newton's 2nd law.

-----Original Message-----
From: judolist- [mailto:judolist-] On Behalf Of Carl Hayes
Sent: Tuesday, April 20, 2010 12:29 PM
To: Discussion of All Aspects of Traditional and Modern Judo
Subject: Re: [JudoList] judo physics **** question

Do they really accelerate slower? Or do they just have a greater distance to travel? But maybe they really do accelerate slower, because after all their mass is proportional to the cube of their height if they are of similar build -- very nonlinear.

So, for example, if you are 10% taller than I am (and built the same), you must move 10% farther, and you must move 33% more mass, too. So you'd better be 44% stronger if you want to move a body length in the same time I move a body length.

Yeah, I'll bet they accelerate slower.

-- Carl
.
----- Original Message -----
From: Jonathan Jeffer
To: Discussion of All Aspects of Traditional and Modern Judo
Sent: Tuesday, April 20, 2010 12:10 PM
Subject: Re: [JudoList] judo physics **** question


What I was wondering about is something I have observed - that big people tend to accelerate slower and change direction slower than smaller people.
The energy needed to accelerate more mass is clear. What I was wonder about was whether it gets harder as mass goes up. What Carl corrected me on is that its not actually harder, because the relationship is linear. Other factors might not be linear. Like the ratio of strength to mass.

--- On Tue, 4/20/10, Richard Porro <> wrote:

From: Richard Porro <>
Subject: Re: [JudoList] judo physics **** question
To: "'Discussion of All Aspects of Traditional and Modern Judo'" <>
Date: Tuesday, April 20, 2010, 11:19 AM

I am not going to forward this to my dojo. I have nothing but engineers.
Including 2 MIT PhD's try to teach this group of people an art. I have said,
"throw to the perpendicular of the line that connects to the back of your
feet" so many times I get light headed every time I go to class. I even
started teaching throws as equations. aaaaaaaaaaaaaaHHHHHHHHHHHHHHHH

Richard Porro

If it isn't full contact, it isn't martial arts!
-----Original Message-----
From: judolist- [mailto:judolist-] On
Behalf Of Jonathan Jeffer
Sent: Monday, April 19, 2010 5:47 PM
To: Judo-L Judo-L
Subject: [JudoList] judo physics **** question

Okay - for the engineers and scientists on the list.
I was thinking about this question -
Its clear that it takes more energy (and greater force) to accelerate a
heavier body than a smaller one. Also to stop heavier body already in
motion. Does anyone know if the relationship of force required to the mass
is linear or exponential? Or - putting it another way as players get
heavier does the force required at the margin go up ?
Jon



_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. See, I knew this would happen, it sounds just like my judo class. 3 minutes
of demonstration. 15 minutes of the math behind it.

Richard Porro

If it isn't full contact, it isn't martial arts!

-----Original Message-----
From: judolist- [mailto:judolist-] On
Behalf Of Carl Hayes
Sent: Tuesday, April 20, 2010 11:29 AM
To: Discussion of All Aspects of Traditional and Modern Judo
Subject: Re: [JudoList] judo physics **** question

Do they really accelerate slower? Or do they just have a greater distance
to travel? But maybe they really do accelerate slower, because after all
their mass is proportional to the cube of their height if they are of
similar build -- very nonlinear.

So, for example, if you are 10% taller than I am (and built the same), you
must move 10% farther, and you must move 33% more mass, too. So you'd
better be 44% stronger if you want to move a body length in the same time I
move a body length.

Yeah, I'll bet they accelerate slower.

-- Carl
.
----- Original Message -----
From: Jonathan Jeffer
To: Discussion of All Aspects of Traditional and Modern Judo
Sent: Tuesday, April 20, 2010 12:10 PM
Subject: Re: [JudoList] judo physics **** question


What I was wondering about is something I have observed - that big people
tend to accelerate slower and change direction slower than smaller people.
The energy needed to accelerate more mass is clear. What I was wonder
about was whether it gets harder as mass goes up. What Carl corrected me on
is that its not actually harder, because the relationship is linear. Other
factors might not be linear. Like the ratio of strength to mass.

--- On Tue, 4/20/10, Richard Porro <> wrote:

From: Richard Porro <>
Subject: Re: [JudoList] judo physics **** question
To: "'Discussion of All Aspects of Traditional and Modern Judo'"
<>
Date: Tuesday, April 20, 2010, 11:19 AM

I am not going to forward this to my dojo. I have nothing but engineers.
Including 2 MIT PhD's try to teach this group of people an art. I have
said,
"throw to the perpendicular of the line that connects to the back of your
feet" so many times I get light headed every time I go to class. I even
started teaching throws as equations. aaaaaaaaaaaaaaHHHHHHHHHHHHHHHH

Richard Porro

If it isn't full contact, it isn't martial arts!
-----Original Message-----
From: judolist- [mailto:judolist-]
On
Behalf Of Jonathan Jeffer
Sent: Monday, April 19, 2010 5:47 PM
To: Judo-L Judo-L
Subject: [JudoList] judo physics **** question

Okay - for the engineers and scientists on the list.
I was thinking about this question -
Its clear that it takes more energy (and greater force) to accelerate a
heavier body than a smaller one. Also to stop heavier body already in
motion. Does anyone know if the relationship of force required to the mass
is linear or exponential? Or - putting it another way as players get
heavier does the force required at the margin go up ?
Jon



_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. There is a really cool older book "The Secrets of Judo" by Jiichi Watanabe. It talks about the physics of judo

-----Original Message-----
From: judolist- [mailto:judolist-] On Behalf Of Richard Porro
Sent: Tuesday, April 20, 2010 12:39 PM
To: 'Discussion of All Aspects of Traditional and Modern Judo'
Subject: Re: [JudoList] judo physics **** question

See, I knew this would happen, it sounds just like my judo class. 3 minutes
of demonstration. 15 minutes of the math behind it.

Richard Porro

If it isn't full contact, it isn't martial arts!

-----Original Message-----
From: judolist- [mailto:judolist-] On
Behalf Of Carl Hayes
Sent: Tuesday, April 20, 2010 11:29 AM
To: Discussion of All Aspects of Traditional and Modern Judo
Subject: Re: [JudoList] judo physics **** question

Do they really accelerate slower? Or do they just have a greater distance
to travel? But maybe they really do accelerate slower, because after all
their mass is proportional to the cube of their height if they are of
similar build -- very nonlinear.

So, for example, if you are 10% taller than I am (and built the same), you
must move 10% farther, and you must move 33% more mass, too. So you'd
better be 44% stronger if you want to move a body length in the same time I
move a body length.

Yeah, I'll bet they accelerate slower.

-- Carl
.
----- Original Message -----
From: Jonathan Jeffer
To: Discussion of All Aspects of Traditional and Modern Judo
Sent: Tuesday, April 20, 2010 12:10 PM
Subject: Re: [JudoList] judo physics **** question


What I was wondering about is something I have observed - that big people
tend to accelerate slower and change direction slower than smaller people.
The energy needed to accelerate more mass is clear. What I was wonder
about was whether it gets harder as mass goes up. What Carl corrected me on
is that its not actually harder, because the relationship is linear. Other
factors might not be linear. Like the ratio of strength to mass.

--- On Tue, 4/20/10, Richard Porro <> wrote:

From: Richard Porro <>
Subject: Re: [JudoList] judo physics **** question
To: "'Discussion of All Aspects of Traditional and Modern Judo'"
<>
Date: Tuesday, April 20, 2010, 11:19 AM

I am not going to forward this to my dojo. I have nothing but engineers.
Including 2 MIT PhD's try to teach this group of people an art. I have
said,
"throw to the perpendicular of the line that connects to the back of your
feet" so many times I get light headed every time I go to class. I even
started teaching throws as equations. aaaaaaaaaaaaaaHHHHHHHHHHHHHHHH

Richard Porro

If it isn't full contact, it isn't martial arts!
-----Original Message-----
From: judolist- [mailto:judolist-]
On
Behalf Of Jonathan Jeffer
Sent: Monday, April 19, 2010 5:47 PM
To: Judo-L Judo-L
Subject: [JudoList] judo physics **** question

Okay - for the engineers and scientists on the list.
I was thinking about this question -
Its clear that it takes more energy (and greater force) to accelerate a
heavier body than a smaller one. Also to stop heavier body already in
motion. Does anyone know if the relationship of force required to the mass
is linear or exponential? Or - putting it another way as players get
heavier does the force required at the margin go up ?
Jon



_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. On Apr 20, 2010, at 9:37 AM, Richard Porro wrote:

> That is true. They don't wait for the off balance and are forced to muscle
> thru. Also another observation is that" big people" tend to force things
> using brute strength first before they even try to off balance Uke.

I think that's too much of a broad generalization. Strength and power are assets. If you have them in ample supply, you would tend to use them, particularly in the absence of other tools. I would offer that your statement is more true with lesser skilled and lesser experienced practitioners. But then... Even the "smaller people" will tend to force things (or "try" to force things) if that's the only option they perceive.

You being a larger person, I think you can totally agree that when you started judo (or karate for that matter), you used a lot more strength and power than you do now that you "know better".


-D. Israel

http://www.customcodebydan.com
AIM: JudoDanIzz

If a dozen smart, successful people who've achieved something great are all giving the same advice, take it.

_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. We can only use general statements when we have such a large group as well
as diverse one. But I agree with you on both your statements

Richard Porro

If it isn't full contact, it isn't martial arts!

-----Original Message-----
From: judolist- [mailto:judolist-] On
Behalf Of Daniel Israel
Sent: Tuesday, April 20, 2010 11:57 AM
To: Discussion of All Aspects of Traditional and Modern Judo
Subject: Re: [JudoList] judo physics **** question


On Apr 20, 2010, at 9:37 AM, Richard Porro wrote:

> That is true. They don't wait for the off balance and are forced to muscle
> thru. Also another observation is that" big people" tend to force things
> using brute strength first before they even try to off balance Uke.

I think that's too much of a broad generalization. Strength and power are
assets. If you have them in ample supply, you would tend to use them,
particularly in the absence of other tools. I would offer that your
statement is more true with lesser skilled and lesser experienced
practitioners. But then... Even the "smaller people" will tend to force
things (or "try" to force things) if that's the only option they perceive.

You being a larger person, I think you can totally agree that when you
started judo (or karate for that matter), you used a lot more strength and
power than you do now that you "know better".


-D. Israel

http://www.customcodebydan.com
AIM: JudoDanIzz

If a dozen smart, successful people who've achieved something great are all
giving the same advice, take it.

_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. i GAVE A DEMO.TO ALMOST ALL THE NEW STUDENTS,I MOVE THEM OFF BALANCE
WITHOUT TOUCHING THE NO MATER HOW BIG THEY ARE..IT MAKES THEM THINK..


In a message dated 4/20/2010 9:38:18 A.M. Pacific Daylight Time,
writes:

Acceleration is force divided by mass. Greater mass equals lower
acceleration. Newton's 2nd law.

-----Original Message-----
From: judolist- [mailto:judolist-]
On Behalf Of Carl Hayes
Sent: Tuesday, April 20, 2010 12:29 PM
To: Discussion of All Aspects of Traditional and Modern Judo
Subject: Re: [JudoList] judo physics **** question

Do they really accelerate slower? Or do they just have a greater distance
to travel? But maybe they really do accelerate slower, because after all
their mass is proportional to the cube of their height if they are of
similar build -- very nonlinear.

So, for example, if you are 10% taller than I am (and built the same), you
must move 10% farther, and you must move 33% more mass, too. So you'd
better be 44% stronger if you want to move a body length in the same time I
move a body length.

Yeah, I'll bet they accelerate slower.

-- Carl
.
----- Original Message -----
From: Jonathan Jeffer
To: Discussion of All Aspects of Traditional and Modern Judo
Sent: Tuesday, April 20, 2010 12:10 PM
Subject: Re: [JudoList] judo physics **** question


What I was wondering about is something I have observed - that big people
tend to accelerate slower and change direction slower than smaller people.
The energy needed to accelerate more mass is clear. What I was wonder
about was whether it gets harder as mass goes up. What Carl corrected me on is
that its not actually harder, because the relationship is linear. Other
factors might not be linear. Like the ratio of strength to mass.

--- On Tue, 4/20/10, Richard Porro <> wrote:

From: Richard Porro <>
Subject: Re: [JudoList] judo physics **** question
To: "'Discussion of All Aspects of Traditional and Modern Judo'"
<>
Date: Tuesday, April 20, 2010, 11:19 AM

I am not going to forward this to my dojo. I have nothing but engineers.
Including 2 MIT PhD's try to teach this group of people an art. I have
said,
"throw to the perpendicular of the line that connects to the back of your
feet" so many times I get light headed every time I go to class. I even
started teaching throws as equations. aaaaaaaaaaaaaaHHHHHHHHHHHHHHHH

Richard Porro

If it isn't full contact, it isn't martial arts!
-----Original Message-----
From: judolist- [mailto:judolist-]
On
Behalf Of Jonathan Jeffer
Sent: Monday, April 19, 2010 5:47 PM
To: Judo-L Judo-L
Subject: [JudoList] judo physics **** question

Okay - for the engineers and scientists on the list.
I was thinking about this question -
Its clear that it takes more energy (and greater force) to accelerate a
heavier body than a smaller one. Also to stop heavier body already in
motion. Does anyone know if the relationship of force required to the mass
is linear or exponential? Or - putting it another way as players get
heavier does the force required at the margin go up ?
Jon



_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe.

Okay - for the engineers and scientists on the list.
I was thinking about this question -
Its clear that it takes more energy (and greater force) to accelerate a heavier body than a smaller one. Also to stop heavier body already in motion.  Does anyone know if the relationship of force required to the mass is linear or exponential?  Or - putting it another way as players get heavier does the force required at the margin go up ?
Jon



_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. For the same acceleration, the force is proportional to the mass. f=ma is a basic foundation of first-semester physics.

-- Carl
.
----- Original Message -----
From: Jonathan Jeffer
To: Judo-L Judo-L
Sent: Monday, April 19, 2010 6:47 PM
Subject: [JudoList] judo physics **** question


Okay - for the engineers and scientists on the list.
I was thinking about this question -
Its clear that it takes more energy (and greater force) to accelerate a heavier body than a smaller one. Also to stop heavier body already in motion. Does anyone know if the relationship of force required to the mass is linear or exponential? Or - putting it another way as players get heavier does the force required at the margin go up ?
Jon



_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. 1st semester was a long time ago. I know the equation I was just not thinking clearly.  Makes sense.


Subject: Re: [JudoList] judo physics **** question
Date: Monday, April 19, 2010, 6:51 PM

For the same acceleration, the force is proportional to the mass.  f=ma is a basic foundation of first-semester physics.

  -- Carl
.
  ----- Original Message -----
  From: Jonathan Jeffer
  To: Judo-L Judo-L
  Sent: Monday, April 19, 2010 6:47 PM
  Subject: [JudoList] judo physics **** question


  Okay - for the engineers and scientists on the list.
  I was thinking about this question -
  Its clear that it takes more energy (and greater force) to accelerate a heavier body than a smaller one. Also to stop heavier body already in motion. Does anyone know if the relationship of force required to the mass is linear or exponential? Or - putting it another way as players get heavier does the force required at the margin go up ?
  Jon


       
  _______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. I am not going to forward this to my dojo. I have nothing but engineers.
Including 2 MIT PhD's try to teach this group of people an art. I have said,
"throw to the perpendicular of the line that connects to the back of your
feet" so many times I get light headed every time I go to class. I even
started teaching throws as equations. aaaaaaaaaaaaaaHHHHHHHHHHHHHHHH

Richard Porro

If it isn't full contact, it isn't martial arts!
-----Original Message-----
From: judolist- [mailto:judolist-] On
Behalf Of Jonathan Jeffer
Sent: Monday, April 19, 2010 5:47 PM
To: Judo-L Judo-L
Subject: [JudoList] judo physics **** question

Okay - for the engineers and scientists on the list.
I was thinking about this question -
Its clear that it takes more energy (and greater force) to accelerate a
heavier body than a smaller one. Also to stop heavier body already in
motion.  Does anyone know if the relationship of force required to the mass
is linear or exponential?  Or - putting it another way as players get
heavier does the force required at the margin go up ?
Jon



_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. Sounds like Monday night class again.:)

Richard Porro

If it isn't full contact, it isn't martial arts!

-----Original Message-----
From: judolist- [mailto:judolist-] On
Behalf Of Carl Hayes
Sent: Monday, April 19, 2010 5:52 PM
To: Discussion of All Aspects of Traditional and Modern Judo
Subject: Re: [JudoList] judo physics **** question

For the same acceleration, the force is proportional to the mass. f=ma is a
basic foundation of first-semester physics.

-- Carl
.
----- Original Message -----
From: Jonathan Jeffer
To: Judo-L Judo-L
Sent: Monday, April 19, 2010 6:47 PM
Subject: [JudoList] judo physics **** question


Okay - for the engineers and scientists on the list.
I was thinking about this question -
Its clear that it takes more energy (and greater force) to accelerate a
heavier body than a smaller one. Also to stop heavier body already in
motion. Does anyone know if the relationship of force required to the mass
is linear or exponential? Or - putting it another way as players get heavier
does the force required at the margin go up ?
Jon



_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. What I was wondering about is something I have observed - that big people tend to accelerate slower and change direction slower  than smaller people.
The energy needed to accelerate more mass is clear.  What I was wonder about was whether it gets harder as mass goes up.  What Carl corrected me on is that its not actually harder, because the relationship is linear.  Other factors might not be linear.  Like the ratio of strength to mass.

--- On Tue, 4/20/10, Richard Porro <> wrote:

From: Richard Porro <>
Subject: Re: [JudoList] judo physics **** question
To: "'Discussion of All Aspects of Traditional and Modern Judo'" <>
Date: Tuesday, April 20, 2010, 11:19 AM

I am not going to forward this to my dojo. I have nothing but engineers.
Including 2 MIT PhD's try to teach this group of people an art. I have said,
"throw to the perpendicular of the line that connects to the back of your
feet" so many times I get light headed every time I go to class. I even
started teaching throws as equations. aaaaaaaaaaaaaaHHHHHHHHHHHHHHHH

Richard Porro

If it isn't full contact, it isn't martial arts!
-----Original Message-----
From: judolist- [mailto:judolist-] On
Behalf Of Jonathan Jeffer
Sent: Monday, April 19, 2010 5:47 PM
To: Judo-L Judo-L
Subject: [JudoList] judo physics **** question

Okay - for the engineers and scientists on the list.
I was thinking about this question -
Its clear that it takes more energy (and greater force) to accelerate a
heavier body than a smaller one. Also to stop heavier body already in
motion.  Does anyone know if the relationship of force required to the mass
is linear or exponential?  Or - putting it another way as players get
heavier does the force required at the margin go up ?
Jon


     
_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. You are correct. It takes longer for a larger person to arrive at the "sweet" spot of no return as my sensei used to say. Most people try to throw to soon and therefore have to force the engagement.


T Ryan





-----Original Message-----
From: Jonathan Jeffer <>
To: Discussion of All Aspects of Traditional and Modern Judo <>
Sent: Tue, Apr 20, 2010 12:10 pm
Subject: Re: [JudoList] judo physics **** question


What I was wondering about is something I have observed - that big people tend
to accelerate slower and change direction slower than smaller people.
The energy needed to accelerate more mass is clear. What I was wonder about was
whether it gets harder as mass goes up. What Carl corrected me on is that its
not actually harder, because the relationship is linear. Other factors might
not be linear. Like the ratio of strength to mass.

--- On Tue, 4/20/10, Richard Porro <> wrote:

From: Richard Porro <>
Subject: Re: [JudoList] judo physics **** question
To: "'Discussion of All Aspects of Traditional and Modern Judo'"
<>
Date: Tuesday, April 20, 2010, 11:19 AM

I am not going to forward this to my dojo. I have nothing but engineers.
Including 2 MIT PhD's try to teach this group of people an art. I have said,
"throw to the perpendicular of the line that connects to the back of your
feet" so many times I get light headed every time I go to class. I even
started teaching throws as equations. aaaaaaaaaaaaaaHHHHHHHHHHHHHHHH

Richard Porro

If it isn't full contact, it isn't martial arts!
-----Original Message-----
From: judolist- [mailto:judolist-] On
Behalf Of Jonathan Jeffer
Sent: Monday, April 19, 2010 5:47 PM
To: Judo-L Judo-L
Subject: [JudoList] judo physics **** question

Okay - for the engineers and scientists on the list.
I was thinking about this question -
Its clear that it takes more energy (and greater force) to accelerate a
heavier body than a smaller one. Also to stop heavier body already in
motion. Does anyone know if the relationship of force required to the mass
is linear or exponential? Or - putting it another way as players get
heavier does the force required at the margin go up ?
Jon



_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. Do they really accelerate slower? Or do they just have a greater distance to travel? But maybe they really do accelerate slower, because after all their mass is proportional to the cube of their height if they are of similar build -- very nonlinear.

So, for example, if you are 10% taller than I am (and built the same), you must move 10% farther, and you must move 33% more mass, too. So you'd better be 44% stronger if you want to move a body length in the same time I move a body length.

Yeah, I'll bet they accelerate slower.

-- Carl
.
----- Original Message -----
From: Jonathan Jeffer
To: Discussion of All Aspects of Traditional and Modern Judo
Sent: Tuesday, April 20, 2010 12:10 PM
Subject: Re: [JudoList] judo physics **** question


What I was wondering about is something I have observed - that big people tend to accelerate slower and change direction slower than smaller people.
The energy needed to accelerate more mass is clear. What I was wonder about was whether it gets harder as mass goes up. What Carl corrected me on is that its not actually harder, because the relationship is linear. Other factors might not be linear. Like the ratio of strength to mass.

--- On Tue, 4/20/10, Richard Porro <> wrote:

From: Richard Porro <>
Subject: Re: [JudoList] judo physics **** question
To: "'Discussion of All Aspects of Traditional and Modern Judo'" <>
Date: Tuesday, April 20, 2010, 11:19 AM

I am not going to forward this to my dojo. I have nothing but engineers.
Including 2 MIT PhD's try to teach this group of people an art. I have said,
"throw to the perpendicular of the line that connects to the back of your
feet" so many times I get light headed every time I go to class. I even
started teaching throws as equations. aaaaaaaaaaaaaaHHHHHHHHHHHHHHHH

Richard Porro

If it isn't full contact, it isn't martial arts!
-----Original Message-----
From: judolist- [mailto:judolist-] On
Behalf Of Jonathan Jeffer
Sent: Monday, April 19, 2010 5:47 PM
To: Judo-L Judo-L
Subject: [JudoList] judo physics **** question

Okay - for the engineers and scientists on the list.
I was thinking about this question -
Its clear that it takes more energy (and greater force) to accelerate a
heavier body than a smaller one. Also to stop heavier body already in
motion. Does anyone know if the relationship of force required to the mass
is linear or exponential? Or - putting it another way as players get
heavier does the force required at the margin go up ?
Jon



_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. That is true. They don't wait for the off balance and are forced to muscle
thru. Also another observation is that" big people" tend to force things
using brute strength first before they even try to off balance Uke.



Richard Porro



If it isn't full contact, it isn't martial arts!



-----Original Message-----
From: judolist- [mailto:judolist-] On
Behalf Of
Sent: Tuesday, April 20, 2010 11:23 AM
To:
Subject: Re: [JudoList] judo physics **** question



You are correct. It takes longer for a larger person to arrive at the
"sweet" spot of no return as my sensei used to say. Most people try to
throw to soon and therefore have to force the engagement.





T Ryan











-----Original Message-----

From: Jonathan Jeffer <>

To: Discussion of All Aspects of Traditional and Modern Judo
<>

Sent: Tue, Apr 20, 2010 12:10 pm

Subject: Re: [JudoList] judo physics **** question





What I was wondering about is something I have observed - that big people
tend

to accelerate slower and change direction slower than smaller people.

The energy needed to accelerate more mass is clear. What I was wonder about
was

whether it gets harder as mass goes up. What Carl corrected me on is that
its

not actually harder, because the relationship is linear. Other factors
might

not be linear. Like the ratio of strength to mass.



--- On Tue, 4/20/10, Richard Porro <> wrote:



From: Richard Porro <>

Subject: Re: [JudoList] judo physics **** question

To: "'Discussion of All Aspects of Traditional and Modern Judo'"

<>

Date: Tuesday, April 20, 2010, 11:19 AM



I am not going to forward this to my dojo. I have nothing but engineers.

Including 2 MIT PhD's try to teach this group of people an art. I have said,

"throw to the perpendicular of the line that connects to the back of your

feet" so many times I get light headed every time I go to class. I even

started teaching throws as equations. aaaaaaaaaaaaaaHHHHHHHHHHHHHHHH



Richard Porro



If it isn't full contact, it isn't martial arts!

-----Original Message-----

From: judolist- [mailto:judolist-] On

Behalf Of Jonathan Jeffer

Sent: Monday, April 19, 2010 5:47 PM

To: Judo-L Judo-L

Subject: [JudoList] judo physics **** question



Okay - for the engineers and scientists on the list.

I was thinking about this question -

Its clear that it takes more energy (and greater force) to accelerate a

heavier body than a smaller one. Also to stop heavier body already in

motion. Does anyone know if the relationship of force required to the mass

is linear or exponential? Or - putting it another way as players get

heavier does the force required at the margin go up ?

Jon







_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. Now THAT's funny, I don't care who you are...



On Tue, Apr 20, 2010 at 8:19 AM, Richard Porro <> wrote:

> I am not going to forward this to my dojo. I have nothing but engineers.
> Including 2 MIT PhD's try to teach this group of people an art. I have
> said,
> "throw to the perpendicular of the line that connects to the back of your
> feet" so many times I get light headed every time I go to class. I even
> started teaching throws as equations. aaaaaaaaaaaaaaHHHHHHHHHHHHHHHH
>
> Richard Porro
>
> If it isn't full contact, it isn't martial arts!
> -----Original Message-----
> From: judolist- [mailto:judolist-]
> On
> Behalf Of Jonathan Jeffer
> Sent: Monday, April 19, 2010 5:47 PM
> To: Judo-L Judo-L
> Subject: [JudoList] judo physics **** question
>
> Okay - for the engineers and scientists on the list.
> I was thinking about this question -
> Its clear that it takes more energy (and greater force) to accelerate a
> heavier body than a smaller one. Also to stop heavier body already in
> motion. Does anyone know if the relationship of force required to the mass
> is linear or exponential? Or - putting it another way as players get
> heavier does the force required at the margin go up ?
> Jon
>
>
>
> _______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. Acceleration is force divided by mass. Greater mass equals lower acceleration. Newton's 2nd law.

-----Original Message-----
From: judolist- [mailto:judolist-] On Behalf Of Carl Hayes
Sent: Tuesday, April 20, 2010 12:29 PM
To: Discussion of All Aspects of Traditional and Modern Judo
Subject: Re: [JudoList] judo physics **** question

Do they really accelerate slower? Or do they just have a greater distance to travel? But maybe they really do accelerate slower, because after all their mass is proportional to the cube of their height if they are of similar build -- very nonlinear.

So, for example, if you are 10% taller than I am (and built the same), you must move 10% farther, and you must move 33% more mass, too. So you'd better be 44% stronger if you want to move a body length in the same time I move a body length.

Yeah, I'll bet they accelerate slower.

-- Carl
.
----- Original Message -----
From: Jonathan Jeffer
To: Discussion of All Aspects of Traditional and Modern Judo
Sent: Tuesday, April 20, 2010 12:10 PM
Subject: Re: [JudoList] judo physics **** question


What I was wondering about is something I have observed - that big people tend to accelerate slower and change direction slower than smaller people.
The energy needed to accelerate more mass is clear. What I was wonder about was whether it gets harder as mass goes up. What Carl corrected me on is that its not actually harder, because the relationship is linear. Other factors might not be linear. Like the ratio of strength to mass.

--- On Tue, 4/20/10, Richard Porro <> wrote:

From: Richard Porro <>
Subject: Re: [JudoList] judo physics **** question
To: "'Discussion of All Aspects of Traditional and Modern Judo'" <>
Date: Tuesday, April 20, 2010, 11:19 AM

I am not going to forward this to my dojo. I have nothing but engineers.
Including 2 MIT PhD's try to teach this group of people an art. I have said,
"throw to the perpendicular of the line that connects to the back of your
feet" so many times I get light headed every time I go to class. I even
started teaching throws as equations. aaaaaaaaaaaaaaHHHHHHHHHHHHHHHH

Richard Porro

If it isn't full contact, it isn't martial arts!
-----Original Message-----
From: judolist- [mailto:judolist-] On
Behalf Of Jonathan Jeffer
Sent: Monday, April 19, 2010 5:47 PM
To: Judo-L Judo-L
Subject: [JudoList] judo physics **** question

Okay - for the engineers and scientists on the list.
I was thinking about this question -
Its clear that it takes more energy (and greater force) to accelerate a
heavier body than a smaller one. Also to stop heavier body already in
motion. Does anyone know if the relationship of force required to the mass
is linear or exponential? Or - putting it another way as players get
heavier does the force required at the margin go up ?
Jon



_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. See, I knew this would happen, it sounds just like my judo class. 3 minutes
of demonstration. 15 minutes of the math behind it.

Richard Porro

If it isn't full contact, it isn't martial arts!

-----Original Message-----
From: judolist- [mailto:judolist-] On
Behalf Of Carl Hayes
Sent: Tuesday, April 20, 2010 11:29 AM
To: Discussion of All Aspects of Traditional and Modern Judo
Subject: Re: [JudoList] judo physics **** question

Do they really accelerate slower? Or do they just have a greater distance
to travel? But maybe they really do accelerate slower, because after all
their mass is proportional to the cube of their height if they are of
similar build -- very nonlinear.

So, for example, if you are 10% taller than I am (and built the same), you
must move 10% farther, and you must move 33% more mass, too. So you'd
better be 44% stronger if you want to move a body length in the same time I
move a body length.

Yeah, I'll bet they accelerate slower.

-- Carl
.
----- Original Message -----
From: Jonathan Jeffer
To: Discussion of All Aspects of Traditional and Modern Judo
Sent: Tuesday, April 20, 2010 12:10 PM
Subject: Re: [JudoList] judo physics **** question


What I was wondering about is something I have observed - that big people
tend to accelerate slower and change direction slower than smaller people.
The energy needed to accelerate more mass is clear. What I was wonder
about was whether it gets harder as mass goes up. What Carl corrected me on
is that its not actually harder, because the relationship is linear. Other
factors might not be linear. Like the ratio of strength to mass.

--- On Tue, 4/20/10, Richard Porro <> wrote:

From: Richard Porro <>
Subject: Re: [JudoList] judo physics **** question
To: "'Discussion of All Aspects of Traditional and Modern Judo'"
<>
Date: Tuesday, April 20, 2010, 11:19 AM

I am not going to forward this to my dojo. I have nothing but engineers.
Including 2 MIT PhD's try to teach this group of people an art. I have
said,
"throw to the perpendicular of the line that connects to the back of your
feet" so many times I get light headed every time I go to class. I even
started teaching throws as equations. aaaaaaaaaaaaaaHHHHHHHHHHHHHHHH

Richard Porro

If it isn't full contact, it isn't martial arts!
-----Original Message-----
From: judolist- [mailto:judolist-]
On
Behalf Of Jonathan Jeffer
Sent: Monday, April 19, 2010 5:47 PM
To: Judo-L Judo-L
Subject: [JudoList] judo physics **** question

Okay - for the engineers and scientists on the list.
I was thinking about this question -
Its clear that it takes more energy (and greater force) to accelerate a
heavier body than a smaller one. Also to stop heavier body already in
motion. Does anyone know if the relationship of force required to the mass
is linear or exponential? Or - putting it another way as players get
heavier does the force required at the margin go up ?
Jon



_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. There is a really cool older book "The Secrets of Judo" by Jiichi Watanabe. It talks about the physics of judo

-----Original Message-----
From: judolist- [mailto:judolist-] On Behalf Of Richard Porro
Sent: Tuesday, April 20, 2010 12:39 PM
To: 'Discussion of All Aspects of Traditional and Modern Judo'
Subject: Re: [JudoList] judo physics **** question

See, I knew this would happen, it sounds just like my judo class. 3 minutes
of demonstration. 15 minutes of the math behind it.

Richard Porro

If it isn't full contact, it isn't martial arts!

-----Original Message-----
From: judolist- [mailto:judolist-] On
Behalf Of Carl Hayes
Sent: Tuesday, April 20, 2010 11:29 AM
To: Discussion of All Aspects of Traditional and Modern Judo
Subject: Re: [JudoList] judo physics **** question

Do they really accelerate slower? Or do they just have a greater distance
to travel? But maybe they really do accelerate slower, because after all
their mass is proportional to the cube of their height if they are of
similar build -- very nonlinear.

So, for example, if you are 10% taller than I am (and built the same), you
must move 10% farther, and you must move 33% more mass, too. So you'd
better be 44% stronger if you want to move a body length in the same time I
move a body length.

Yeah, I'll bet they accelerate slower.

-- Carl
.
----- Original Message -----
From: Jonathan Jeffer
To: Discussion of All Aspects of Traditional and Modern Judo
Sent: Tuesday, April 20, 2010 12:10 PM
Subject: Re: [JudoList] judo physics **** question


What I was wondering about is something I have observed - that big people
tend to accelerate slower and change direction slower than smaller people.
The energy needed to accelerate more mass is clear. What I was wonder
about was whether it gets harder as mass goes up. What Carl corrected me on
is that its not actually harder, because the relationship is linear. Other
factors might not be linear. Like the ratio of strength to mass.

--- On Tue, 4/20/10, Richard Porro <> wrote:

From: Richard Porro <>
Subject: Re: [JudoList] judo physics **** question
To: "'Discussion of All Aspects of Traditional and Modern Judo'"
<>
Date: Tuesday, April 20, 2010, 11:19 AM

I am not going to forward this to my dojo. I have nothing but engineers.
Including 2 MIT PhD's try to teach this group of people an art. I have
said,
"throw to the perpendicular of the line that connects to the back of your
feet" so many times I get light headed every time I go to class. I even
started teaching throws as equations. aaaaaaaaaaaaaaHHHHHHHHHHHHHHHH

Richard Porro

If it isn't full contact, it isn't martial arts!
-----Original Message-----
From: judolist- [mailto:judolist-]
On
Behalf Of Jonathan Jeffer
Sent: Monday, April 19, 2010 5:47 PM
To: Judo-L Judo-L
Subject: [JudoList] judo physics **** question

Okay - for the engineers and scientists on the list.
I was thinking about this question -
Its clear that it takes more energy (and greater force) to accelerate a
heavier body than a smaller one. Also to stop heavier body already in
motion. Does anyone know if the relationship of force required to the mass
is linear or exponential? Or - putting it another way as players get
heavier does the force required at the margin go up ?
Jon



_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. On Apr 20, 2010, at 9:37 AM, Richard Porro wrote:

> That is true. They don't wait for the off balance and are forced to muscle
> thru. Also another observation is that" big people" tend to force things
> using brute strength first before they even try to off balance Uke.

I think that's too much of a broad generalization. Strength and power are assets. If you have them in ample supply, you would tend to use them, particularly in the absence of other tools. I would offer that your statement is more true with lesser skilled and lesser experienced practitioners. But then... Even the "smaller people" will tend to force things (or "try" to force things) if that's the only option they perceive.

You being a larger person, I think you can totally agree that when you started judo (or karate for that matter), you used a lot more strength and power than you do now that you "know better".


-D. Israel

http://www.customcodebydan.com
AIM: JudoDanIzz

If a dozen smart, successful people who've achieved something great are all giving the same advice, take it.

_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. We can only use general statements when we have such a large group as well
as diverse one. But I agree with you on both your statements

Richard Porro

If it isn't full contact, it isn't martial arts!

-----Original Message-----
From: judolist- [mailto:judolist-] On
Behalf Of Daniel Israel
Sent: Tuesday, April 20, 2010 11:57 AM
To: Discussion of All Aspects of Traditional and Modern Judo
Subject: Re: [JudoList] judo physics **** question


On Apr 20, 2010, at 9:37 AM, Richard Porro wrote:

> That is true. They don't wait for the off balance and are forced to muscle
> thru. Also another observation is that" big people" tend to force things
> using brute strength first before they even try to off balance Uke.

I think that's too much of a broad generalization. Strength and power are
assets. If you have them in ample supply, you would tend to use them,
particularly in the absence of other tools. I would offer that your
statement is more true with lesser skilled and lesser experienced
practitioners. But then... Even the "smaller people" will tend to force
things (or "try" to force things) if that's the only option they perceive.

You being a larger person, I think you can totally agree that when you
started judo (or karate for that matter), you used a lot more strength and
power than you do now that you "know better".


-D. Israel

http://www.customcodebydan.com
AIM: JudoDanIzz

If a dozen smart, successful people who've achieved something great are all
giving the same advice, take it.

_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. i GAVE A DEMO.TO ALMOST ALL THE NEW STUDENTS,I MOVE THEM OFF BALANCE
WITHOUT TOUCHING THE NO MATER HOW BIG THEY ARE..IT MAKES THEM THINK..


In a message dated 4/20/2010 9:38:18 A.M. Pacific Daylight Time,
writes:

Acceleration is force divided by mass. Greater mass equals lower
acceleration. Newton's 2nd law.

-----Original Message-----
From: judolist- [mailto:judolist-]
On Behalf Of Carl Hayes
Sent: Tuesday, April 20, 2010 12:29 PM
To: Discussion of All Aspects of Traditional and Modern Judo
Subject: Re: [JudoList] judo physics **** question

Do they really accelerate slower? Or do they just have a greater distance
to travel? But maybe they really do accelerate slower, because after all
their mass is proportional to the cube of their height if they are of
similar build -- very nonlinear.

So, for example, if you are 10% taller than I am (and built the same), you
must move 10% farther, and you must move 33% more mass, too. So you'd
better be 44% stronger if you want to move a body length in the same time I
move a body length.

Yeah, I'll bet they accelerate slower.

-- Carl
.
----- Original Message -----
From: Jonathan Jeffer
To: Discussion of All Aspects of Traditional and Modern Judo
Sent: Tuesday, April 20, 2010 12:10 PM
Subject: Re: [JudoList] judo physics **** question


What I was wondering about is something I have observed - that big people
tend to accelerate slower and change direction slower than smaller people.
The energy needed to accelerate more mass is clear. What I was wonder
about was whether it gets harder as mass goes up. What Carl corrected me on is
that its not actually harder, because the relationship is linear. Other
factors might not be linear. Like the ratio of strength to mass.

--- On Tue, 4/20/10, Richard Porro <> wrote:

From: Richard Porro <>
Subject: Re: [JudoList] judo physics **** question
To: "'Discussion of All Aspects of Traditional and Modern Judo'"
<>
Date: Tuesday, April 20, 2010, 11:19 AM

I am not going to forward this to my dojo. I have nothing but engineers.
Including 2 MIT PhD's try to teach this group of people an art. I have
said,
"throw to the perpendicular of the line that connects to the back of your
feet" so many times I get light headed every time I go to class. I even
started teaching throws as equations. aaaaaaaaaaaaaaHHHHHHHHHHHHHHHH

Richard Porro

If it isn't full contact, it isn't martial arts!
-----Original Message-----
From: judolist- [mailto:judolist-]
On
Behalf Of Jonathan Jeffer
Sent: Monday, April 19, 2010 5:47 PM
To: Judo-L Judo-L
Subject: [JudoList] judo physics **** question

Okay - for the engineers and scientists on the list.
I was thinking about this question -
Its clear that it takes more energy (and greater force) to accelerate a
heavier body than a smaller one. Also to stop heavier body already in
motion. Does anyone know if the relationship of force required to the mass
is linear or exponential? Or - putting it another way as players get
heavier does the force required at the margin go up ?
Jon



_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. The other variable would be something like the ratio of strength to mass. Maybe smaller people are stronger by the pound?

--- On Tue, 4/20/10, Carl Hayes <> wrote:

From: Carl Hayes <>
Subject: Re: [JudoList] judo physics **** question
To: "Discussion of All Aspects of Traditional and Modern Judo" <>
Date: Tuesday, April 20, 2010, 12:28 PM

Do they really accelerate slower?  Or do they just have a greater distance to travel?  But maybe they really do accelerate slower, because after all their mass is proportional to the cube of their height if they are of similar build -- very nonlinear.

So, for example, if you are 10% taller than I am (and built the same), you must move 10% farther, and you must move 33% more mass, too.  So you'd better be 44% stronger if you want to move a body length in the same time I move a body length.

Yeah, I'll bet they accelerate slower.

  -- Carl
.
  ----- Original Message -----
  From: Jonathan Jeffer
  To: Discussion of All Aspects of Traditional and Modern Judo
  Sent: Tuesday, April 20, 2010 12:10 PM
  Subject: Re: [JudoList] judo physics **** question


  What I was wondering about is something I have observed - that big people tend to accelerate slower and change direction slower than smaller people.
  The energy needed to accelerate more mass is clear. What I was wonder about was whether it gets harder as mass goes up. What Carl corrected me on is that its not actually harder, because the relationship is linear. Other factors might not be linear. Like the ratio of strength to mass.

  --- On Tue, 4/20/10, Richard Porro <> wrote:

  From: Richard Porro <>
  Subject: Re: [JudoList] judo physics **** question
  To: "'Discussion of All Aspects of Traditional and Modern Judo'" <>
  Date: Tuesday, April 20, 2010, 11:19 AM

  I am not going to forward this to my dojo. I have nothing but engineers.
  Including 2 MIT PhD's try to teach this group of people an art. I have said,
  "throw to the perpendicular of the line that connects to the back of your
  feet" so many times I get light headed every time I go to class. I even
  started teaching throws as equations. aaaaaaaaaaaaaaHHHHHHHHHHHHHHHH

  Richard Porro
   
  If it isn't full contact, it isn't martial arts!
  -----Original Message-----
  From: judolist- [mailto:judolist-] On
  Behalf Of Jonathan Jeffer
  Sent: Monday, April 19, 2010 5:47 PM
  To: Judo-L Judo-L
  Subject: [JudoList] judo physics **** question

  Okay - for the engineers and scientists on the list.
  I was thinking about this question -
  Its clear that it takes more energy (and greater force) to accelerate a
  heavier body than a smaller one. Also to stop heavier body already in
  motion. Does anyone know if the relationship of force required to the mass
  is linear or exponential? Or - putting it another way as players get
  heavier does the force required at the margin go up ?
  Jon



  _______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe.

Okay - for the engineers and scientists on the list.
I was thinking about this question -
Its clear that it takes more energy (and greater force) to accelerate a heavier body than a smaller one. Also to stop heavier body already in motion.  Does anyone know if the relationship of force required to the mass is linear or exponential?  Or - putting it another way as players get heavier does the force required at the margin go up ?
Jon



_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. For the same acceleration, the force is proportional to the mass. f=ma is a basic foundation of first-semester physics.

-- Carl
.
----- Original Message -----
From: Jonathan Jeffer
To: Judo-L Judo-L
Sent: Monday, April 19, 2010 6:47 PM
Subject: [JudoList] judo physics **** question


Okay - for the engineers and scientists on the list.
I was thinking about this question -
Its clear that it takes more energy (and greater force) to accelerate a heavier body than a smaller one. Also to stop heavier body already in motion. Does anyone know if the relationship of force required to the mass is linear or exponential? Or - putting it another way as players get heavier does the force required at the margin go up ?
Jon



_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. 1st semester was a long time ago. I know the equation I was just not thinking clearly.  Makes sense.


Subject: Re: [JudoList] judo physics **** question
Date: Monday, April 19, 2010, 6:51 PM

For the same acceleration, the force is proportional to the mass.  f=ma is a basic foundation of first-semester physics.

  -- Carl
.
  ----- Original Message -----
  From: Jonathan Jeffer
  To: Judo-L Judo-L
  Sent: Monday, April 19, 2010 6:47 PM
  Subject: [JudoList] judo physics **** question


  Okay - for the engineers and scientists on the list.
  I was thinking about this question -
  Its clear that it takes more energy (and greater force) to accelerate a heavier body than a smaller one. Also to stop heavier body already in motion. Does anyone know if the relationship of force required to the mass is linear or exponential? Or - putting it another way as players get heavier does the force required at the margin go up ?
  Jon


       
  _______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. I am not going to forward this to my dojo. I have nothing but engineers.
Including 2 MIT PhD's try to teach this group of people an art. I have said,
"throw to the perpendicular of the line that connects to the back of your
feet" so many times I get light headed every time I go to class. I even
started teaching throws as equations. aaaaaaaaaaaaaaHHHHHHHHHHHHHHHH

Richard Porro

If it isn't full contact, it isn't martial arts!
-----Original Message-----
From: judolist- [mailto:judolist-] On
Behalf Of Jonathan Jeffer
Sent: Monday, April 19, 2010 5:47 PM
To: Judo-L Judo-L
Subject: [JudoList] judo physics **** question

Okay - for the engineers and scientists on the list.
I was thinking about this question -
Its clear that it takes more energy (and greater force) to accelerate a
heavier body than a smaller one. Also to stop heavier body already in
motion.  Does anyone know if the relationship of force required to the mass
is linear or exponential?  Or - putting it another way as players get
heavier does the force required at the margin go up ?
Jon



_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. Sounds like Monday night class again.:)

Richard Porro

If it isn't full contact, it isn't martial arts!

-----Original Message-----
From: judolist- [mailto:judolist-] On
Behalf Of Carl Hayes
Sent: Monday, April 19, 2010 5:52 PM
To: Discussion of All Aspects of Traditional and Modern Judo
Subject: Re: [JudoList] judo physics **** question

For the same acceleration, the force is proportional to the mass. f=ma is a
basic foundation of first-semester physics.

-- Carl
.
----- Original Message -----
From: Jonathan Jeffer
To: Judo-L Judo-L
Sent: Monday, April 19, 2010 6:47 PM
Subject: [JudoList] judo physics **** question


Okay - for the engineers and scientists on the list.
I was thinking about this question -
Its clear that it takes more energy (and greater force) to accelerate a
heavier body than a smaller one. Also to stop heavier body already in
motion. Does anyone know if the relationship of force required to the mass
is linear or exponential? Or - putting it another way as players get heavier
does the force required at the margin go up ?
Jon



_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. What I was wondering about is something I have observed - that big people tend to accelerate slower and change direction slower  than smaller people.
The energy needed to accelerate more mass is clear.  What I was wonder about was whether it gets harder as mass goes up.  What Carl corrected me on is that its not actually harder, because the relationship is linear.  Other factors might not be linear.  Like the ratio of strength to mass.

--- On Tue, 4/20/10, Richard Porro <> wrote:

From: Richard Porro <>
Subject: Re: [JudoList] judo physics **** question
To: "'Discussion of All Aspects of Traditional and Modern Judo'" <>
Date: Tuesday, April 20, 2010, 11:19 AM

I am not going to forward this to my dojo. I have nothing but engineers.
Including 2 MIT PhD's try to teach this group of people an art. I have said,
"throw to the perpendicular of the line that connects to the back of your
feet" so many times I get light headed every time I go to class. I even
started teaching throws as equations. aaaaaaaaaaaaaaHHHHHHHHHHHHHHHH

Richard Porro

If it isn't full contact, it isn't martial arts!
-----Original Message-----
From: judolist- [mailto:judolist-] On
Behalf Of Jonathan Jeffer
Sent: Monday, April 19, 2010 5:47 PM
To: Judo-L Judo-L
Subject: [JudoList] judo physics **** question

Okay - for the engineers and scientists on the list.
I was thinking about this question -
Its clear that it takes more energy (and greater force) to accelerate a
heavier body than a smaller one. Also to stop heavier body already in
motion.  Does anyone know if the relationship of force required to the mass
is linear or exponential?  Or - putting it another way as players get
heavier does the force required at the margin go up ?
Jon


     
_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. You are correct. It takes longer for a larger person to arrive at the "sweet" spot of no return as my sensei used to say. Most people try to throw to soon and therefore have to force the engagement.


T Ryan





-----Original Message-----
From: Jonathan Jeffer <>
To: Discussion of All Aspects of Traditional and Modern Judo <>
Sent: Tue, Apr 20, 2010 12:10 pm
Subject: Re: [JudoList] judo physics **** question


What I was wondering about is something I have observed - that big people tend
to accelerate slower and change direction slower than smaller people.
The energy needed to accelerate more mass is clear. What I was wonder about was
whether it gets harder as mass goes up. What Carl corrected me on is that its
not actually harder, because the relationship is linear. Other factors might
not be linear. Like the ratio of strength to mass.

--- On Tue, 4/20/10, Richard Porro <> wrote:

From: Richard Porro <>
Subject: Re: [JudoList] judo physics **** question
To: "'Discussion of All Aspects of Traditional and Modern Judo'"
<>
Date: Tuesday, April 20, 2010, 11:19 AM

I am not going to forward this to my dojo. I have nothing but engineers.
Including 2 MIT PhD's try to teach this group of people an art. I have said,
"throw to the perpendicular of the line that connects to the back of your
feet" so many times I get light headed every time I go to class. I even
started teaching throws as equations. aaaaaaaaaaaaaaHHHHHHHHHHHHHHHH

Richard Porro

If it isn't full contact, it isn't martial arts!
-----Original Message-----
From: judolist- [mailto:judolist-] On
Behalf Of Jonathan Jeffer
Sent: Monday, April 19, 2010 5:47 PM
To: Judo-L Judo-L
Subject: [JudoList] judo physics **** question

Okay - for the engineers and scientists on the list.
I was thinking about this question -
Its clear that it takes more energy (and greater force) to accelerate a
heavier body than a smaller one. Also to stop heavier body already in
motion. Does anyone know if the relationship of force required to the mass
is linear or exponential? Or - putting it another way as players get
heavier does the force required at the margin go up ?
Jon



_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. Do they really accelerate slower? Or do they just have a greater distance to travel? But maybe they really do accelerate slower, because after all their mass is proportional to the cube of their height if they are of similar build -- very nonlinear.

So, for example, if you are 10% taller than I am (and built the same), you must move 10% farther, and you must move 33% more mass, too. So you'd better be 44% stronger if you want to move a body length in the same time I move a body length.

Yeah, I'll bet they accelerate slower.

-- Carl
.
----- Original Message -----
From: Jonathan Jeffer
To: Discussion of All Aspects of Traditional and Modern Judo
Sent: Tuesday, April 20, 2010 12:10 PM
Subject: Re: [JudoList] judo physics **** question


What I was wondering about is something I have observed - that big people tend to accelerate slower and change direction slower than smaller people.
The energy needed to accelerate more mass is clear. What I was wonder about was whether it gets harder as mass goes up. What Carl corrected me on is that its not actually harder, because the relationship is linear. Other factors might not be linear. Like the ratio of strength to mass.

--- On Tue, 4/20/10, Richard Porro <> wrote:

From: Richard Porro <>
Subject: Re: [JudoList] judo physics **** question
To: "'Discussion of All Aspects of Traditional and Modern Judo'" <>
Date: Tuesday, April 20, 2010, 11:19 AM

I am not going to forward this to my dojo. I have nothing but engineers.
Including 2 MIT PhD's try to teach this group of people an art. I have said,
"throw to the perpendicular of the line that connects to the back of your
feet" so many times I get light headed every time I go to class. I even
started teaching throws as equations. aaaaaaaaaaaaaaHHHHHHHHHHHHHHHH

Richard Porro

If it isn't full contact, it isn't martial arts!
-----Original Message-----
From: judolist- [mailto:judolist-] On
Behalf Of Jonathan Jeffer
Sent: Monday, April 19, 2010 5:47 PM
To: Judo-L Judo-L
Subject: [JudoList] judo physics **** question

Okay - for the engineers and scientists on the list.
I was thinking about this question -
Its clear that it takes more energy (and greater force) to accelerate a
heavier body than a smaller one. Also to stop heavier body already in
motion. Does anyone know if the relationship of force required to the mass
is linear or exponential? Or - putting it another way as players get
heavier does the force required at the margin go up ?
Jon



_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. That is true. They don't wait for the off balance and are forced to muscle
thru. Also another observation is that" big people" tend to force things
using brute strength first before they even try to off balance Uke.



Richard Porro



If it isn't full contact, it isn't martial arts!



-----Original Message-----
From: judolist- [mailto:judolist-] On
Behalf Of
Sent: Tuesday, April 20, 2010 11:23 AM
To:
Subject: Re: [JudoList] judo physics **** question



You are correct. It takes longer for a larger person to arrive at the
"sweet" spot of no return as my sensei used to say. Most people try to
throw to soon and therefore have to force the engagement.





T Ryan











-----Original Message-----

From: Jonathan Jeffer <>

To: Discussion of All Aspects of Traditional and Modern Judo
<>

Sent: Tue, Apr 20, 2010 12:10 pm

Subject: Re: [JudoList] judo physics **** question





What I was wondering about is something I have observed - that big people
tend

to accelerate slower and change direction slower than smaller people.

The energy needed to accelerate more mass is clear. What I was wonder about
was

whether it gets harder as mass goes up. What Carl corrected me on is that
its

not actually harder, because the relationship is linear. Other factors
might

not be linear. Like the ratio of strength to mass.



--- On Tue, 4/20/10, Richard Porro <> wrote:



From: Richard Porro <>

Subject: Re: [JudoList] judo physics **** question

To: "'Discussion of All Aspects of Traditional and Modern Judo'"

<>

Date: Tuesday, April 20, 2010, 11:19 AM



I am not going to forward this to my dojo. I have nothing but engineers.

Including 2 MIT PhD's try to teach this group of people an art. I have said,

"throw to the perpendicular of the line that connects to the back of your

feet" so many times I get light headed every time I go to class. I even

started teaching throws as equations. aaaaaaaaaaaaaaHHHHHHHHHHHHHHHH



Richard Porro



If it isn't full contact, it isn't martial arts!

-----Original Message-----

From: judolist- [mailto:judolist-] On

Behalf Of Jonathan Jeffer

Sent: Monday, April 19, 2010 5:47 PM

To: Judo-L Judo-L

Subject: [JudoList] judo physics **** question



Okay - for the engineers and scientists on the list.

I was thinking about this question -

Its clear that it takes more energy (and greater force) to accelerate a

heavier body than a smaller one. Also to stop heavier body already in

motion. Does anyone know if the relationship of force required to the mass

is linear or exponential? Or - putting it another way as players get

heavier does the force required at the margin go up ?

Jon







_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. Now THAT's funny, I don't care who you are...



On Tue, Apr 20, 2010 at 8:19 AM, Richard Porro <> wrote:

> I am not going to forward this to my dojo. I have nothing but engineers.
> Including 2 MIT PhD's try to teach this group of people an art. I have
> said,
> "throw to the perpendicular of the line that connects to the back of your
> feet" so many times I get light headed every time I go to class. I even
> started teaching throws as equations. aaaaaaaaaaaaaaHHHHHHHHHHHHHHHH
>
> Richard Porro
>
> If it isn't full contact, it isn't martial arts!
> -----Original Message-----
> From: judolist- [mailto:judolist-]
> On
> Behalf Of Jonathan Jeffer
> Sent: Monday, April 19, 2010 5:47 PM
> To: Judo-L Judo-L
> Subject: [JudoList] judo physics **** question
>
> Okay - for the engineers and scientists on the list.
> I was thinking about this question -
> Its clear that it takes more energy (and greater force) to accelerate a
> heavier body than a smaller one. Also to stop heavier body already in
> motion. Does anyone know if the relationship of force required to the mass
> is linear or exponential? Or - putting it another way as players get
> heavier does the force required at the margin go up ?
> Jon
>
>
>
> _______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. Acceleration is force divided by mass. Greater mass equals lower acceleration. Newton's 2nd law.

-----Original Message-----
From: judolist- [mailto:judolist-] On Behalf Of Carl Hayes
Sent: Tuesday, April 20, 2010 12:29 PM
To: Discussion of All Aspects of Traditional and Modern Judo
Subject: Re: [JudoList] judo physics **** question

Do they really accelerate slower? Or do they just have a greater distance to travel? But maybe they really do accelerate slower, because after all their mass is proportional to the cube of their height if they are of similar build -- very nonlinear.

So, for example, if you are 10% taller than I am (and built the same), you must move 10% farther, and you must move 33% more mass, too. So you'd better be 44% stronger if you want to move a body length in the same time I move a body length.

Yeah, I'll bet they accelerate slower.

-- Carl
.
----- Original Message -----
From: Jonathan Jeffer
To: Discussion of All Aspects of Traditional and Modern Judo
Sent: Tuesday, April 20, 2010 12:10 PM
Subject: Re: [JudoList] judo physics **** question


What I was wondering about is something I have observed - that big people tend to accelerate slower and change direction slower than smaller people.
The energy needed to accelerate more mass is clear. What I was wonder about was whether it gets harder as mass goes up. What Carl corrected me on is that its not actually harder, because the relationship is linear. Other factors might not be linear. Like the ratio of strength to mass.

--- On Tue, 4/20/10, Richard Porro <> wrote:

From: Richard Porro <>
Subject: Re: [JudoList] judo physics **** question
To: "'Discussion of All Aspects of Traditional and Modern Judo'" <>
Date: Tuesday, April 20, 2010, 11:19 AM

I am not going to forward this to my dojo. I have nothing but engineers.
Including 2 MIT PhD's try to teach this group of people an art. I have said,
"throw to the perpendicular of the line that connects to the back of your
feet" so many times I get light headed every time I go to class. I even
started teaching throws as equations. aaaaaaaaaaaaaaHHHHHHHHHHHHHHHH

Richard Porro

If it isn't full contact, it isn't martial arts!
-----Original Message-----
From: judolist- [mailto:judolist-] On
Behalf Of Jonathan Jeffer
Sent: Monday, April 19, 2010 5:47 PM
To: Judo-L Judo-L
Subject: [JudoList] judo physics **** question

Okay - for the engineers and scientists on the list.
I was thinking about this question -
Its clear that it takes more energy (and greater force) to accelerate a
heavier body than a smaller one. Also to stop heavier body already in
motion. Does anyone know if the relationship of force required to the mass
is linear or exponential? Or - putting it another way as players get
heavier does the force required at the margin go up ?
Jon



_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. See, I knew this would happen, it sounds just like my judo class. 3 minutes
of demonstration. 15 minutes of the math behind it.

Richard Porro

If it isn't full contact, it isn't martial arts!

-----Original Message-----
From: judolist- [mailto:judolist-] On
Behalf Of Carl Hayes
Sent: Tuesday, April 20, 2010 11:29 AM
To: Discussion of All Aspects of Traditional and Modern Judo
Subject: Re: [JudoList] judo physics **** question

Do they really accelerate slower? Or do they just have a greater distance
to travel? But maybe they really do accelerate slower, because after all
their mass is proportional to the cube of their height if they are of
similar build -- very nonlinear.

So, for example, if you are 10% taller than I am (and built the same), you
must move 10% farther, and you must move 33% more mass, too. So you'd
better be 44% stronger if you want to move a body length in the same time I
move a body length.

Yeah, I'll bet they accelerate slower.

-- Carl
.
----- Original Message -----
From: Jonathan Jeffer
To: Discussion of All Aspects of Traditional and Modern Judo
Sent: Tuesday, April 20, 2010 12:10 PM
Subject: Re: [JudoList] judo physics **** question


What I was wondering about is something I have observed - that big people
tend to accelerate slower and change direction slower than smaller people.
The energy needed to accelerate more mass is clear. What I was wonder
about was whether it gets harder as mass goes up. What Carl corrected me on
is that its not actually harder, because the relationship is linear. Other
factors might not be linear. Like the ratio of strength to mass.

--- On Tue, 4/20/10, Richard Porro <> wrote:

From: Richard Porro <>
Subject: Re: [JudoList] judo physics **** question
To: "'Discussion of All Aspects of Traditional and Modern Judo'"
<>
Date: Tuesday, April 20, 2010, 11:19 AM

I am not going to forward this to my dojo. I have nothing but engineers.
Including 2 MIT PhD's try to teach this group of people an art. I have
said,
"throw to the perpendicular of the line that connects to the back of your
feet" so many times I get light headed every time I go to class. I even
started teaching throws as equations. aaaaaaaaaaaaaaHHHHHHHHHHHHHHHH

Richard Porro

If it isn't full contact, it isn't martial arts!
-----Original Message-----
From: judolist- [mailto:judolist-]
On
Behalf Of Jonathan Jeffer
Sent: Monday, April 19, 2010 5:47 PM
To: Judo-L Judo-L
Subject: [JudoList] judo physics **** question

Okay - for the engineers and scientists on the list.
I was thinking about this question -
Its clear that it takes more energy (and greater force) to accelerate a
heavier body than a smaller one. Also to stop heavier body already in
motion. Does anyone know if the relationship of force required to the mass
is linear or exponential? Or - putting it another way as players get
heavier does the force required at the margin go up ?
Jon



_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. There is a really cool older book "The Secrets of Judo" by Jiichi Watanabe. It talks about the physics of judo

-----Original Message-----
From: judolist- [mailto:judolist-] On Behalf Of Richard Porro
Sent: Tuesday, April 20, 2010 12:39 PM
To: 'Discussion of All Aspects of Traditional and Modern Judo'
Subject: Re: [JudoList] judo physics **** question

See, I knew this would happen, it sounds just like my judo class. 3 minutes
of demonstration. 15 minutes of the math behind it.

Richard Porro

If it isn't full contact, it isn't martial arts!

-----Original Message-----
From: judolist- [mailto:judolist-] On
Behalf Of Carl Hayes
Sent: Tuesday, April 20, 2010 11:29 AM
To: Discussion of All Aspects of Traditional and Modern Judo
Subject: Re: [JudoList] judo physics **** question

Do they really accelerate slower? Or do they just have a greater distance
to travel? But maybe they really do accelerate slower, because after all
their mass is proportional to the cube of their height if they are of
similar build -- very nonlinear.

So, for example, if you are 10% taller than I am (and built the same), you
must move 10% farther, and you must move 33% more mass, too. So you'd
better be 44% stronger if you want to move a body length in the same time I
move a body length.

Yeah, I'll bet they accelerate slower.

-- Carl
.
----- Original Message -----
From: Jonathan Jeffer
To: Discussion of All Aspects of Traditional and Modern Judo
Sent: Tuesday, April 20, 2010 12:10 PM
Subject: Re: [JudoList] judo physics **** question


What I was wondering about is something I have observed - that big people
tend to accelerate slower and change direction slower than smaller people.
The energy needed to accelerate more mass is clear. What I was wonder
about was whether it gets harder as mass goes up. What Carl corrected me on
is that its not actually harder, because the relationship is linear. Other
factors might not be linear. Like the ratio of strength to mass.

--- On Tue, 4/20/10, Richard Porro <> wrote:

From: Richard Porro <>
Subject: Re: [JudoList] judo physics **** question
To: "'Discussion of All Aspects of Traditional and Modern Judo'"
<>
Date: Tuesday, April 20, 2010, 11:19 AM

I am not going to forward this to my dojo. I have nothing but engineers.
Including 2 MIT PhD's try to teach this group of people an art. I have
said,
"throw to the perpendicular of the line that connects to the back of your
feet" so many times I get light headed every time I go to class. I even
started teaching throws as equations. aaaaaaaaaaaaaaHHHHHHHHHHHHHHHH

Richard Porro

If it isn't full contact, it isn't martial arts!
-----Original Message-----
From: judolist- [mailto:judolist-]
On
Behalf Of Jonathan Jeffer
Sent: Monday, April 19, 2010 5:47 PM
To: Judo-L Judo-L
Subject: [JudoList] judo physics **** question

Okay - for the engineers and scientists on the list.
I was thinking about this question -
Its clear that it takes more energy (and greater force) to accelerate a
heavier body than a smaller one. Also to stop heavier body already in
motion. Does anyone know if the relationship of force required to the mass
is linear or exponential? Or - putting it another way as players get
heavier does the force required at the margin go up ?
Jon



_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. On Apr 20, 2010, at 9:37 AM, Richard Porro wrote:

> That is true. They don't wait for the off balance and are forced to muscle
> thru. Also another observation is that" big people" tend to force things
> using brute strength first before they even try to off balance Uke.

I think that's too much of a broad generalization. Strength and power are assets. If you have them in ample supply, you would tend to use them, particularly in the absence of other tools. I would offer that your statement is more true with lesser skilled and lesser experienced practitioners. But then... Even the "smaller people" will tend to force things (or "try" to force things) if that's the only option they perceive.

You being a larger person, I think you can totally agree that when you started judo (or karate for that matter), you used a lot more strength and power than you do now that you "know better".


-D. Israel

http://www.customcodebydan.com
AIM: JudoDanIzz

If a dozen smart, successful people who've achieved something great are all giving the same advice, take it.

_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. We can only use general statements when we have such a large group as well
as diverse one. But I agree with you on both your statements

Richard Porro

If it isn't full contact, it isn't martial arts!

-----Original Message-----
From: judolist- [mailto:judolist-] On
Behalf Of Daniel Israel
Sent: Tuesday, April 20, 2010 11:57 AM
To: Discussion of All Aspects of Traditional and Modern Judo
Subject: Re: [JudoList] judo physics **** question


On Apr 20, 2010, at 9:37 AM, Richard Porro wrote:

> That is true. They don't wait for the off balance and are forced to muscle
> thru. Also another observation is that" big people" tend to force things
> using brute strength first before they even try to off balance Uke.

I think that's too much of a broad generalization. Strength and power are
assets. If you have them in ample supply, you would tend to use them,
particularly in the absence of other tools. I would offer that your
statement is more true with lesser skilled and lesser experienced
practitioners. But then... Even the "smaller people" will tend to force
things (or "try" to force things) if that's the only option they perceive.

You being a larger person, I think you can totally agree that when you
started judo (or karate for that matter), you used a lot more strength and
power than you do now that you "know better".


-D. Israel

http://www.customcodebydan.com
AIM: JudoDanIzz

If a dozen smart, successful people who've achieved something great are all
giving the same advice, take it.

_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. i GAVE A DEMO.TO ALMOST ALL THE NEW STUDENTS,I MOVE THEM OFF BALANCE
WITHOUT TOUCHING THE NO MATER HOW BIG THEY ARE..IT MAKES THEM THINK..


In a message dated 4/20/2010 9:38:18 A.M. Pacific Daylight Time,
writes:

Acceleration is force divided by mass. Greater mass equals lower
acceleration. Newton's 2nd law.

-----Original Message-----
From: judolist- [mailto:judolist-]
On Behalf Of Carl Hayes
Sent: Tuesday, April 20, 2010 12:29 PM
To: Discussion of All Aspects of Traditional and Modern Judo
Subject: Re: [JudoList] judo physics **** question

Do they really accelerate slower? Or do they just have a greater distance
to travel? But maybe they really do accelerate slower, because after all
their mass is proportional to the cube of their height if they are of
similar build -- very nonlinear.

So, for example, if you are 10% taller than I am (and built the same), you
must move 10% farther, and you must move 33% more mass, too. So you'd
better be 44% stronger if you want to move a body length in the same time I
move a body length.

Yeah, I'll bet they accelerate slower.

-- Carl
.
----- Original Message -----
From: Jonathan Jeffer
To: Discussion of All Aspects of Traditional and Modern Judo
Sent: Tuesday, April 20, 2010 12:10 PM
Subject: Re: [JudoList] judo physics **** question


What I was wondering about is something I have observed - that big people
tend to accelerate slower and change direction slower than smaller people.
The energy needed to accelerate more mass is clear. What I was wonder
about was whether it gets harder as mass goes up. What Carl corrected me on is
that its not actually harder, because the relationship is linear. Other
factors might not be linear. Like the ratio of strength to mass.

--- On Tue, 4/20/10, Richard Porro <> wrote:

From: Richard Porro <>
Subject: Re: [JudoList] judo physics **** question
To: "'Discussion of All Aspects of Traditional and Modern Judo'"
<>
Date: Tuesday, April 20, 2010, 11:19 AM

I am not going to forward this to my dojo. I have nothing but engineers.
Including 2 MIT PhD's try to teach this group of people an art. I have
said,
"throw to the perpendicular of the line that connects to the back of your
feet" so many times I get light headed every time I go to class. I even
started teaching throws as equations. aaaaaaaaaaaaaaHHHHHHHHHHHHHHHH

Richard Porro

If it isn't full contact, it isn't martial arts!
-----Original Message-----
From: judolist- [mailto:judolist-]
On
Behalf Of Jonathan Jeffer
Sent: Monday, April 19, 2010 5:47 PM
To: Judo-L Judo-L
Subject: [JudoList] judo physics **** question

Okay - for the engineers and scientists on the list.
I was thinking about this question -
Its clear that it takes more energy (and greater force) to accelerate a
heavier body than a smaller one. Also to stop heavier body already in
motion. Does anyone know if the relationship of force required to the mass
is linear or exponential? Or - putting it another way as players get
heavier does the force required at the margin go up ?
Jon



_______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. The other variable would be something like the ratio of strength to mass. Maybe smaller people are stronger by the pound?

--- On Tue, 4/20/10, Carl Hayes <> wrote:

From: Carl Hayes <>
Subject: Re: [JudoList] judo physics **** question
To: "Discussion of All Aspects of Traditional and Modern Judo" <>
Date: Tuesday, April 20, 2010, 12:28 PM

Do they really accelerate slower?  Or do they just have a greater distance to travel?  But maybe they really do accelerate slower, because after all their mass is proportional to the cube of their height if they are of similar build -- very nonlinear.

So, for example, if you are 10% taller than I am (and built the same), you must move 10% farther, and you must move 33% more mass, too.  So you'd better be 44% stronger if you want to move a body length in the same time I move a body length.

Yeah, I'll bet they accelerate slower.

  -- Carl
.
  ----- Original Message -----
  From: Jonathan Jeffer
  To: Discussion of All Aspects of Traditional and Modern Judo
  Sent: Tuesday, April 20, 2010 12:10 PM
  Subject: Re: [JudoList] judo physics **** question


  What I was wondering about is something I have observed - that big people tend to accelerate slower and change direction slower than smaller people.
  The energy needed to accelerate more mass is clear. What I was wonder about was whether it gets harder as mass goes up. What Carl corrected me on is that its not actually harder, because the relationship is linear. Other factors might not be linear. Like the ratio of strength to mass.

  --- On Tue, 4/20/10, Richard Porro <> wrote:

  From: Richard Porro <>
  Subject: Re: [JudoList] judo physics **** question
  To: "'Discussion of All Aspects of Traditional and Modern Judo'" <>
  Date: Tuesday, April 20, 2010, 11:19 AM

  I am not going to forward this to my dojo. I have nothing but engineers.
  Including 2 MIT PhD's try to teach this group of people an art. I have said,
  "throw to the perpendicular of the line that connects to the back of your
  feet" so many times I get light headed every time I go to class. I even
  started teaching throws as equations. aaaaaaaaaaaaaaHHHHHHHHHHHHHHHH

  Richard Porro
   
  If it isn't full contact, it isn't martial arts!
  -----Original Message-----
  From: judolist- [mailto:judolist-] On
  Behalf Of Jonathan Jeffer
  Sent: Monday, April 19, 2010 5:47 PM
  To: Judo-L Judo-L
  Subject: [JudoList] judo physics **** question

  Okay - for the engineers and scientists on the list.
  I was thinking about this question -
  Its clear that it takes more energy (and greater force) to accelerate a
  heavier body than a smaller one. Also to stop heavier body already in
  motion. Does anyone know if the relationship of force required to the mass
  is linear or exponential? Or - putting it another way as players get
  heavier does the force required at the margin go up ?
  Jon



  _______________________________________________
___________________________________________________

Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe. I also have observed that bigger people take longer to rock back - I always compared it to a pendulum with a heavier weight.

--- On Tue, 4/20/10, Richard Porro <> wrote:

From: Richard Porro <>
Subject: Re: [JudoList] judo physics **** question
To: "'Discussion of All Aspects of Traditional and Modern Judo'" <>
Date: Tuesday, April 20, 2010, 12:37 PM

That is true. They don't wait for the off balance and are forced to muscle
thru. Also another observation is that" big people" tend to force things
using brute strength first before they even try to off balance Uke.



Richard Porro



If it isn't full contact, it isn't martial arts!



-----Original Message-----
From: judolist- [mailto:judolist-] On
Behalf Of
Sent: Tuesday, April 20, 2010 11:23 AM
To:
Subject: Re: [JudoList] judo physics **** question



You are correct.  It takes longer for a larger person to arrive at the
"sweet" spot of no return as my sensei used to say.  Most people try to
throw to soon and therefore have to force the engagement.





T Ryan











-----Original Message-----

From: Jonathan Jeffer <>

To: Discussion of All Aspects of Traditional and Modern Judo
<>

Sent: Tue, Apr 20, 2010 12:10 pm

Subject: Re: [JudoList] judo physics **** question





What I was wondering about is something I have observed - that big people
tend

to accelerate slower and change direction slower  than smaller people.

The energy needed to accelerate more mass is clear.  What I was wonder about
was

whether it gets harder as mass goes up.  What Carl corrected me on is that
its

not actually harder, because the relationship is linear.  Other factors
might

not be linear.  Like the ratio of strength to mass.



--- On Tue, 4/20/10, Richard Porro <> wrote:



From: Richard Porro <>

Subject: Re: [JudoList] judo physics **** question

To: "'Discussion of All Aspects of Traditional and Modern Judo'"

<>

Date: Tuesday, April 20, 2010, 11:19 AM



I am not going to forward this to my dojo. I have nothing but engineers.

Including 2 MIT PhD's try to teach this group of people an art. I have said,

"throw to the perpendicular of the line that connects to the back of your

feet" so many times I get light headed every time I go to class. I even

started teaching throws as equations. aaaaaaaaaaaaaaHHHHHHHHHHHHHHHH



Richard Porro



If it isn't full contact, it isn't martial arts!

-----Original Message-----

From: judolist- [mailto:judolist-] On

Behalf Of Jonathan Jeffer

Sent: Monday, April 19, 2010 5:47 PM

To: Judo-L Judo-L

Subject: [JudoList] judo physics **** question



Okay - for the engineers and scientists on the list.

I was thinking about this question -

Its clear that it takes more energy (and greater force) to accelerate a

heavier body than a smaller one. Also to stop heavier body already in

motion.  Does anyone know if the relationship of force required to the mass

is linear or exponential?  Or - putting it another way as players get

heavier does the force required at the margin go up ?

Jon





     

_______________________________________________
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Posted on the JudoList mailing list. Go to http://mail.chas-ma.com/mailman/listinfo/judolist_chas-ma.com to subscribe.