Posted by: RH (goodstewardmail@cs.com) on Wed Feb 6 12:05:15 2002

There are a couple of issues I would like to ask for help understanding. The first has to do with the linear vs. rotational motion. For the life of me, I can't tell by looking at a batter swinging if he's "throwing his hands to the ball" or using rotational mechanics. For that matter, I can't tell if I'm doing it right. I think what I need to see is an overhead view, to actually see the arcing path of the bat. I just can't tell from a ground level view.

The second is the idea of hand torque. I can understand the top-hand back, bottom hand forward torquing as the first move in the swing. It agrees with the 4-way lugwrench metaphor that Jack illustrates - each hand is pulling toward itself, thus putting opposite forces on the bat and torquing the head rearward. But that analogy falls apart when the bat starts moving towards the pitcher. Now the bottom hand is pulling forward and the top hand is pushing forward. How does this create the same type of torque as the first move?? It seems like a little word voodoo - in both instances the hands are putting forces FROM opposite diretions, but during the forward swing, they are applying force TOWARDS the same direction (towards the ball). Both moves cannot possibly create the same torque dynamic.

Another case of word voodoo (or my lack of understanding) has to do with the finishing stroke. The bottom hand "pulling towards the catcher", the top hand pushing "towards the pitcher". Sounds like opposite force torque - but let's not kid ourselves, they are moving in the same direction! In clock terms, the bottom has passed 12 and is moving towards 6, but the top hand has not passed 12 so is moving towards 12. But they are in different spots on the SAME arc path, so obviously they are moving in the SAME direction. If the forces were in opposite directions, they would offset and the swing would stop cold.

Before anyone writes me off, yes I have read the whole site, printed out the articles and the swing analysis and read all the material several times. I'm not talking through my hat. If I have a real misconception of the physics concepts being discussed, please enlighten me.