Hitting and Hitters Discussion Swing Analysis

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NASCAR is NOT a sport

There have been a couple of mentions about centripetal force. Centripetal force is a kinematic force requirement, not a true force and does not apply to Newtons laws of motion. I believe the swing creates a centrifugal force (a kinetic force) which does apply to Newtons laws of motion (f=ma). Just before impact, the hitters body (reference frame) starts their hips, arms, hands, trunk, shoulders (axis of rotation) causing an outward force (centrifugal force). I might be wrong since I have not studied Dynamics in about 25 years....... :-/

Len

Len could not get the chart to load however if you go this site under item 8 you will find it http://www.physics.usyd.edu.au/~cross/baseball.html

Thanks Howard

 

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Howard


I think I will stick with your, easy to teach to a 12 year old girl method.




Straightleg

 

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Straightleg you asked for it.

 

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God knows I hate it when Howard goes technical on me. ;D ;D ;D ;D

D**N Engineers.

Elliott.

 

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I bet it was very entertaining to be present when you two were talking softball in Oklahoma .

 

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Dan sometimes Elliot has a bit of an English accent and then confuses me!

Got ya!

 

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Hi Howard and Sammy

Sammy.....I knew exactly what you were talking about. I totally agree with you about using new technologies. I just hate NASCAR! It was nothing against your post.


Howard.....thanks for the links. I must admit that I made a huge error in my first post. I knew what I meant, but my thoughts did not travel to my typing. Of course a centripetal force requirement pertains to Newton's "Laws Of Motion". I meant to say that since it is a kinematic force requirement you cannot use f=ma to calculate a trajectory, which was actually cut and pasted by you from Wikipedia so thank you for correcting my statement.

So what does "centripetal force requirement" mean? It simply means that centriptel force is a force requirement necessary for a curved trajectory to be possible. It is nothing more than an implied force. Another force is doing the work, and I believe that force is centrifugal force.

http://www.physicsnews1.com/question_5.html

There is a great debate amongst physicists about whether centrifugal force is ficticous or real. I believe it is real because it can be proven. The physicists that deny centrifugal force is a real force are the ones that do not want to sway from what they were taught. They're afraid the walls would crumble around them. They would rather call the rotational outward fleeing force with magnitude and direction "torque". It's amazing that torque can be real but centrifugal force must remain fictitious.

The other link you provided to me had a section called "How To Swing A Bat". The author calculates centripetal force as if it were a kinetic force. Also, he is observing it from an external reference point instead of putting himself in the middle of the rotational reference frame. He also thinks that a batter swings with his or her arms and a little wrist action, totally ignoring the larger muscles in the trunk and legs used in swinging a bat correctly. Basically, his calculations and observations provided very little useful information in my opinion other than the push/pull forces on the bat handle, which of course are helping the bat to rotate. The author is basically denying the existence of centrifugal force due to what he was taught in my opinion.

The end result of a hit is a ball following a vector, ie. the ball is hit with magnitude and direction. This vector is the result of a net force acting on the ball. According to Dynamics, this net force must be kinetic so it cannot be centripetal force.

Your opinions may vary.....Physics is an inexact science.

Len

 

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Len

Whenever I hear rotational I think of Epstein twirling a ball on a rope and telling everyone this is rotational hitting and this is how it works.

After looking at enough film and watching enough kids hit live I have stopped using the words rotational because it appears to me the hands move some what linear and then as the shoulders, hips and upper and lower arm start to unhinge it is anything yet even close to rotational from where we started our actual motion and movement to swing.....at best it may be elliptical or semi circular however not purely rotational enough to tag it with that name.

I like the merry go round explanation that if you are at the outside edge of it you are feeling something happening to your body and that may be best described as centrifugal force and the direction is centripetal.

I feel we release the forces using the shoulder, upper and lower arms and finally the wrists to hit the ball and some others feel it is the action of centripetal forces that causes it and I think it is caused and initiated by the hitters instincts.

 

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Hi Howard

I'm not a huge fan of Epstein either. ?And I agree, a full swing is not circular rather it is more in the shape of an ellipse. ?To me, rotation means nothing more than a turn, and I believe that a hitter's hips and shoulders do turn. ?I do agree with you that the hands and arms movements are more linear.

Howard wrote:
[highlight]I feel we release the forces using the shoulder, upper and lower arms and finally the wrists to hit the ball and some others feel it is the action of centripetal forces that causes it and I think it is caused and initiated by the hitters instincts.[/highlight]

In other words, hit the ball solid kid! ;D ;D ;D

Len

 

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Amen!