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Re: A INTERESTING QUESTION (fwd)



On Mon, 4 Jan 1999, Joseph Bellina wrote:

I got this question from a local baseball coach. Any advice?

joe
Prof. Bellina:
I've been working on a project for this spring and summer for my
softball and baseball squads. We've been experimenting with wood and
aluminum bats, trying to see which one would be the best to use. I set
up a scenerio like this. There are two hitters of equal size and
strength. One hitter uses an aluminum bat, 33" long and weighing 27
ounces. Batter #2, uses a wood bat, 33 " long and weighing 31 ounces.
The hitter with aluminum has a bat speed of 75 mph, the hitter with wood
has a bat speed of 70 mph. They are both facing a pitcher who is
throwing the ball 75 mph. (this is assuming however that because the
aluminum is lighter, one can swing it faster)Given their swings and
other atmospheric conditions are equal......does the ball come off the
aluminum faster or the wood bat and does the ball travel further off
the aluminum or the wood? How would that change if the wood bat hitter
has the same bat speed of the player using the aluminum bat?
I'm not sure if you need any other particulars for this problem,
but if you do please let me know and I'll try to fill in those gaps.

Thanks for the help!!!

John Kovach

In order to determine the speed of the ball (wrt ground) after being hit,
you need to know the rebound angle wrt the incident velocity direction of
the ball (assuming the bat's velocity is exactly opposite the ball's).
You also must assume something about the hitter. The easiest assumption
is that he has no effect on the bat (i.e., no follow through force) after
impact. Assuming that the bat and ball collide elastically, will give the
maximum recoil ball speed. You can make more realistic assumptions about
the coefficient of elasticity between bat and ball--wood and aluminum are
probably not the same.

In order to determine the distance the ball travels (range) you need to
know the angle of its velocity wrt the ground after leaving the bat.

You can probably find more realistic info from an article or book on the
physics of baseball--see earlier discussions on this list.

Have phun with this physics,
bob

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