The AFU and Urban Legend Archive
Science
 baseball physics




From: phil@rahul.net (Phil Gustafson)
Subject: Re: Accelerating pitch UL, maybe NEW!
Date: Wed, 1 Sep 1993 22:31:49 GMT

Jason W. Nyberg writes:

>I had an argument with my roomate and his father who tried to
>convince me that when a pitcher throws a fastball, the ball
>actually accelerates while it travels to the plate. He told me
>that his high school baseball coach told him about it. He told
>me "Roger Clemens' arm doesn't go 100 mph!" He told me, "They
>measure it wit radar right at the mound, and right at the plate.
>At the mound, the ball is only going 60-70 mph, but by the time
>the ball crosses the plate it could be going 90-100 mph." He
>told me, "It's not in physics books." :)
>
>I told him that he, his father, and his coach were full of shit.
>:)

You get ten points for accuracy, minus three for lack of tact, and minus ten for the smiley.

Check out _The Physics of Baseball_ by Robert K. Adair (Harper and Row, 1990, ISBN 0-06-096461-8). Adair is Sterling Professor of Physics at Yale University and, from 1987 to 1989, Physicist to the National League:

...the "muzzle velocity" of the ball -- as it leaves the pitcher's hand -- is about 8 mph greater than its speed across the plate. The ball loses speed at the rate of about 1 mph every 7 feet.

This means that a very fast fast ball leaves the hand of the pitcher at well over 100 mph: at the plate measured speeds include 98.6 (Feller, 1946), 99.7 (Johnson, 1914, though how they got the number I don't know), and 100.7 (Ryan, no date) mph. Johnson claimed that Dr. Smokey Joe Wood was even faster. Add 8 mph to each for the speed at the hand.

Check out the book if you're interested in baseball, Magnus coefficients, and Reynolds numbers.

And this is a new sports UL, at least to me.

"Fenway" Phil Gustafson
--
Phil Gustafson <phil@rahul.net>


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