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FINDING A NEW ANGLE ON BASEBALL
Penny Ward Moser
April 09, 1990
Here's the perfect book to enlighten all your friends who think that Magnus force is a TV show currently in afternoon reruns: The Physics of Baseball (Harper & Row, $7.95), by Robert Kemp Adair, Sterling Professor of Physics at Yale.
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April 09, 1990

Finding A New Angle On Baseball

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Here's the perfect book to enlighten all your friends who think that Magnus force is a TV show currently in afternoon reruns: The Physics of Baseball (Harper & Row, $7.95), by Robert Kemp Adair, Sterling Professor of Physics at Yale.

In a delightful preface, we learn how the late Bart Giamatti, who had been president of Yale before becoming president of the National League and then commissioner of baseball, inspired the work by asking his former colleague to advise him on some of the more technical elements of baseball. In return, Giamatti appointed Adair "Physicist to the National League"—a job with no pay but with, Adair says, "a title that absolutely charmed the 10-year-old boy who I hope will always be a part of me."

The Physics of Baseball dazzles one with information and offers a tough, brain-stretching read. Adair says the book was "written for fun" and "is not meant as a scholarly compendium of research on baseball." Egad, if this is fun, I shudder to think of what he considers scholarly writing.

To be fair, there are some very fun facts, but I felt like a sandpiper at low tide, wading around sticking my head in the thick mud to find them. The best ones I pulled up include the following:

?A curveball—and here's where you'll learn all about Magnus force—thrown by a righthanded pitcher at 70 mph may rotate 17 times on its 60'6" journey. That's 1,800 rpm, or half the rate of a small synchronous electric motor.

?In 1921, Cool Papa Bell of the Negro leagues is said to have run the bases in less than 13 seconds—barely one second slower than Carl Lewis could theoretically run that 120-yard distance in a straight line.

?The collision of the bat, itself going 70 mph, and the ball, traveling at 90 mph, lasts only about [1/1000] of a second. It takes nearly 8,000 pounds of force to change the motion of the 5?-ounce ball from its speed of 90 mph toward the plate to a speed of 110 mph toward the centerfield bleachers. Swing [1/100] of a second late, and it's foul.

Other facts: In the 1961 All-Star Game in San Francisco, a balk was called on Stu Miller of the Giants when a gust of wind blew him off the mound. A ball batted with an initial velocity of 110 mph at an angle of 35 degrees from the horizontal would go about 750 feet in a vacuum; near sea level at Shea Stadium it would travel only about 400 feet; at Atlanta's 1,050-foot altitude it would go 408 feet; in Kansas City, 406 feet; in Chicago or Milwaukee, 405 feet. But if Denver is ever granted a franchise, the equivalent 400-foot drive by Darryl Strawberry in Shea would go an amazing 440 feet in a mile-high stadium. And a batted ball will travel 20 feet farther on a 95� day than on a 45� day.

But once past these nuggets, I found myself in mud as the syntax became virtually opaque. To understand the flight of a baseball, Adair tells us, we must know this:

"When an object (such as a baseball) passes through a fluid (such as air), the fluid affects the motion of the object as it flows about the object. Moreover, for all fluids and all objects, the character of the flow of the fluid is determined by the value of a (dimensionless) Reynolds number proportional to the density of the fluid, the fluid velocity, the size of the object, and inversely proportional to the viscosity of the fluid. For a given Reynolds number, the behavior of the gaseous fluid of stars—interacting with each other through gravity—that make up a galaxy 100,000 light-years across is described in very much the same way as the behavior of the molecules of air passing through an orifice one micron across, where a micron is about equal to the resolution of a high-power microscope."

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