| “The Physics of the Sweet Spot” |
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Physicists unlock secret of baseball bat’s “Sweet Spot”
August 1, 2003
Computer simulations and lab experiments are helping scientists understand what makes a good swing. When a baseball bat hits the ball in what the players call the “sweet spot”, less energy goes into making the bat vibrate and more goes into the ball, making it go further.
-American Institute of Physics
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Sweet spot
People often refer to the sweet spots of a bat. What is this “sweet spot”? The sweet spot is the location on the bat where the ball will travel the furthest distance. It is often referred to as the “fat part” of the bat because it is the thickest part of the bat. Remember that the thickest part of the bat is only as wide as the ball. Another reason why hitters hit better with an aluminum bat is because it has a great area of a sweet spot.
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Bending modes and the sweet spot
There are many definitions for what constitutes the “sweet spot” on a baseball bat. From a player’s viewpoint, the sweet spot is the place on the bat barrel where the contact between bat and ball results in the best hit– the ball leave the bat with the greatest speed and the player’s hands feel very little vibration from the impact. Most often in the published research the sweet spot is usually referred to as either the center of percussion (COP) or the node of the first bending mode. In my study of baseball bats I prefer to follow the convention used by Rod Cross who defines the sweet zone as the region located between the nodes of the first and second modes of vibration (between about 4-7 inches from the barrel end of a 30-inch Little League bat). Since the vibrational motion of the bat is very small in this region, an impact in this region will result in very little vibration of the bat (no stinging a player’s hands) and a very solid hit will result with maximum energy being given to the ball. An impact to the outside (towards the barrel end) or inside (towards the handle) of this zone will result in a much more significant vibration of the bat, often felt as a painful sting. And the ball will not travel as far because some of the energy is now being stored (or dissipated) in the bat’s vibration.
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Acoustics of Baseball Bats
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| Daniel A. Russell |
| Science & Mathematics Department, Kettering University, Flint, MI 48504-4898 |
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References
[1] H. Brody, "The Sweet Spot of a Baseball Bat," American Journal of Physics, 54(7), 640-643 (1986)
[2] R. Cross, "The Sweet Spot of a Baseball Bat," American Journal of Physics, 66(9), 771-779 (1998)
[3] H. Brody, "Models of Baseball Bats," American Journal of Physics, 58(8), 756-758 (1990)
[4] J. Braham, "Keep your eye on the bat," Machine Design, 69(13), 56-66 (July 10, 1997)
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