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Re: .Bernoulli and curve balls.



R. Tarara asks which way curve balls spin and which way they curve.

A right handed pitcher imparts a spin which if viewed from above appears
to be counter clockwise. This causes the ball to break away from a right
handed batter. In reality the spin axis is not vertical and the ball really
breaks down and away. As I recall early editions of Ostdeik and Bord argued
that there would be lower pressure on the side of the ball which was moving
at a higher speed relative to stationary air and that the ball would curve in
to a right handed batter. This section does not appear in more recent
editions of the text.
The Physics of Baseball by Robert K Adair, Harper & Row, $7.95 is a great
little book.

I agree with David Dockstader's opinion of "The Physics of Baseball"; it's very
informative.

Experience as a pitcher (and as a server in volleyball) has shown me that the
standard right-hand curve ball will curve down and away. When thrown "sidearm"
you get what is known as a "roundhouse curve", which is flatter. This pitch
curves away from a right-handed hitter, making it harder to hit (a receding
target!). The baseball lore as I received it says that this is why the
fraction of left-handed batters is much higher than the fraction of
left-handers in the general population: because left-handed batters have a
competetive edge when facing a right-handed pitcher.

Of course, the old adage that "defense evolves to meet the evolution of
offense" applies to baseball. The answer to left-handed batters is ...
left-handed pitchers!

It is possible (though hard on the wrist and elbow) to throw a curveball with
the "opposite" spin (i.e. clockwise as seen from above); the result is a
backwards curve or "screwball" as thrown by such pitchers as Tug McGraw. It is
even possible to grip the seams of the ball som that you throw it with a little
backspin, creating a "rising fastball" (actually, a fastball that doesn't drop
as much as expected due to gravity).

Apparently, technical practice is still ahead of theory. The "palmball", the
"split-finger fastball" and the famous "knuckleball" make the ball curve or
turn in various directions. Clearly more research is needed.

Regards, PRB


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Patrick R. Briggs __ __ __
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