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Re: .Bernoulli and curve balls.



Cut the inner cardboard cylinder from the inside of a paper towel roll to
form a trough. Leave a handle by not cutting all the way to the end. Then
place a styrofoam ball in the trough, and throw the ball using the trough
which will cause the ball to spin.

The quality of curves you can get using this simple apparatus is amazing.
It is quite easy to study the relationship between the spin and the curve.
Try it out!

Alternatively you can purchase a WHAM-O "Trak Ball" or one of its
Asian infringers. You can make a ball curve upwards very easily
with it. I always use it just after I explain to my class that
Galileo determined that the ballistic trajectory is a parabola -
this is the concave upwards case! The point, of course, is that
air can affect the result, sometimes dramatically.

I have not seen a good explanation of the curve ball phenomenon
in any elementary text, and it certainly does not belong in a
textbook at the level of Miller.

Leigh