Posted by: Jack Mankin (MrBatspeed@aol.com) on Tue Dec 11 12:46:25 2007

Hi Daw & All

In my above post, I stated “Dr. Yeager concludes that hip and shoulder rotation is generated from the transfer of momentum as the front leg stops the body’s forward movement. Although I disagree with that conclusion, I do not wish to make it a point of debate at this time. Let us just acknowledge that the batter is rotating around a stationary axis and discuss how that rotation is transferred into bat speed. “

I think this may be a good time to point out my concerns with Dr. Yeager’s theory that the body’s linear momentum attained during the stride is transferred into hip and shoulder rotation. But first, we must all be in agreement with what “momentum” is. Webster’s Dictionary defines “Momentum” as, “the quantity of motion of a moving object, equal to product of its mass and its velocity.”

It is vital for our discussion that we agree that the momentum of an object is equal to the “product of its mass and its velocity.” Therefore, as the velocity of an object approaches zero, its momentum approaches zero. This also means that once an object slows to a stop, that object has zero momentum to do further work.

And there within lies my problem with Dr. Yeager’s theory. I would like to show video clips of the swing to point these concerns. But before I do, does anyone disagree with the definition of “momentum,” or the conclusions I draw from that definition?

Jack Mankin