The Science of Spin: Spin on Baseball

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The direction of baseballs after they are thrown is caused by spin on the ball. Spin is defined as rotations around the axis of the baseball. Major league pitchers have clocked the spin on their pitches at 1500rpm so when a baseball is spinning through the air the threads on the ball cause a self-made “air pocket” that causes changes in direction. This is known as the Magnus affect.
The spin on a baseball is defined as a vector that points on the axis’s rotation. And the magnitude of this spin vector is the number of revolutions per/sec, this is known as an angular velocity vector (Horney, A., Lowry, T., Schwenker, E., & wray, E. (2008). A New spin on baseball. Electronic Proceedings of Undergraduate Mathematics, 3(4)). All baseballs are affected by this spin and the spin is what causes the change in direction. When fastballs are thrown the spin of the ball affects the ball and makes it travel through the air at a higher velocity. It also makes the air mass beneath the ball greater and makes the air above the ball thinner. That creates lift and is what makes the ball faster and causes more speed.
A curveball almost is the exact opposite of a fastball. While a fastball spins and makes the pitch fly strait a curveball spins the opposite way. The downward spin makes the air around the pitch heavy on the top and lighter on the bottom; this causes the ball to drop, or break. According to Mlb.coms game day application a typical major league pitched curveball is averaged at less than 80 mph. While the average fastball pitch is greater than 87 mph.
The next data is from the curveballs of Bronson arroyo from the Cincinnati reds, and the fastballs of Josh Beckett of the Boston red socks. Although the nature of movement on a curveball su...

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... of the ball.
The lift is only important to the spin of the baseball if it is a fastball because the ball creates its own lift.
There are several ways in the 1920’s that pitchers use to cheat by adding friction to the balls in illegal ways. The pitchers would sometimes use pine tar, tobacco juice, or mud on the baseballs the affect the grip and friction of the ball. This caused the balls to be affected even more by the baseballs spin. Pitchers would also use lotion or file down the ball to make it smoother so that he base balls could be travel through the air faster. This was banned because it could cause the pitches to become wild and endanger the batter.

Works Cited

(http://www.grc.nasa.gov/WWW/k-12/airplane/ballforce.html Horney, A., Lowry, T., Schwenker, E., & wray, E. (2008). A New spin on baseball. Electronic Proceedings of Undergraduate Mathematics, 3(4)).

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