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The spin on baseball: WVU experts break down the physics of America’s favorite pastime

With MLB up to bat for opening day (July 23), two West Virginia University astrophysicists are hurling a fastball of science at us to better understand the game.

WVU Department of Physics and Astronomy faculty D.J. Pisano, chair and professor, and Sean McWilliams, associate professor, have combined their love of baseball and physics in the classroom, displays and exhibits for educating youth and even research (Pisano discussed pro baseball stadiums in his thesis).

Watch as they explain the physics behind hitting a home run, wood versus aluminum bats and pitching a curveball in this video.


(On hitting a homer)

“When the bat collides with a ball, you are transferring the momentum (the product of mass times velocity) from the bat to the ball. To maximize the momentum of the bat, you can either increase the mass of the bat or swing the bat faster. The speed which you can swing a bat, however, depends not on the actual mass of the bat but on its ‘swing weight,’ or moment of inertia.”

(On wood versus aluminum bats)

“The average major league baseball player will swing a bat at about 60 mph. With a solid wood bat there is relatively little compression, and a ball pitched at 90 mph will bounce off with an exit velocity of 90 mph. An aluminum bat, however, is hollow, and can exhibit a larger trampoline effect, sending the same ball out with an exit velocity closer to 100 mph.” —D.J. Pisano, chair and professor, WVU Department of Physics and Astronomy

(On pitches)

“If a ball is thrown with a forward spin instead of the usually backward spin, then the deflection is downward and produces a vertical drop greater than what we would expect from gravity alone; this is known as a curveball. If the spin is partially sideways, then the deflection is both down and sideways, and the pitch is called a slider. Both pitches operate due to the same principle, which is also the principle that produces lift as air passes around a wing and allows airplanes to fly.” —Sean McWilliams, associate professor, WVU Department of Physics and Astronomy

Additional Resources

VIDEO: The Physics of Baseball

The Physics of Baseball: WVU Magazine story

West Virginia University experts can provide commentary, insights and opinions on various news topics. Search for an expert by name, title, area of expertise, or college/school/department in the Experts Database at WVU Today.



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WVU Research Communications


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