Posted by: Jack Mankin (MrBatspeed@aol.com) on Fri Dec 3 15:26:34 2004

>>> Jack, that's not much of a response to " The torque being generated by rotating the torso (shoulders). This has been my position from day one. Most everything else is reactive to the rotation of the torso/shoulders. You cannot instantaneously moved a mass from zero to maximum speed without applying an infinite amount of force. Same thing is true with rotation. You cannot rotate something from a rest position to maximum angular velocity unless you apply infinite torque. In this case the infinite torque is being applied by the rotation of the torso and everything else is holding on for dear life as it accelerates up to rotational speed."
How can you begin to address the concerns if, from the above statements (which are only a part of the entire thread) all you have to say is "Do you dispute the definition of torque in my post to Tom? ". Will you at least address the concerns in the above statements? <<<

Hi Dale

You stated, “In this case the infinite torque is being applied by the rotation of the torso.” I refer to what you described as the “bat welded to a wheel” method of applying torque where the hands are held at a relatively fixed position and the bat rotates at basically the same angular velocity as the body rotates.

I have taught this method to beginning students. However, it produces limited bat speed because it does not allow for torque applied to the bat from the push/pull of the forearms supplied from rotational transfer mechanics. That is why I presented the test (below) for your opinion.

>> The right hand is held at a fixed position while a bat is cocked away from a heavy bag about 90 degrees by the lead-shoulder counter-rotating the lead-arm and bottom-hand forward. While keeping the right hand in a fairly fixed position, the bat is then accelerated to contact by the rotation of the lead-shoulder. <<<

With this test, the hands did not rotate with the body rotation as you described. The right-hand remained stationary as the bottom-hand was pulled around it. This test shows that torque is also applied from the push/pull actions of the arms as per the definition of torque – “Forces applied from opposing directions that cause an object to rotate around an axis.”

Jack Mankin