May 19, 2007


Anatomy of a Home Run: In less time than it takes to blink an eye, pro hitters routinely achieve the extraordinary. (Davin Coburn, June 2007 , Popular Mechanics)

A bat vibrates at multiple frequencies when it collides with a ball. How much energy is transferred to the ball — instead of spread through the bat and the batter’s hands — depends on where the collision occurs. A bat vibrating at its fundamental frequency has a node of zero vibration about 6 1/2 in. from the barrel end (Node 1). This was long thought to be the bat’s sweet spot. But Rod Cross, a physicist at Australia’s University of Sydney, found that the spot is more like a zone. At a second frequency (in red), a bat has another node about 4 1/2 in. down the barrel (Node 2). Hits between the two produce minimal vibration — and transfer more energy — at both frequencies. "Every ball I’ve hit that I haven’t felt, I knew I hit well," Zimmerman says.

Boosting two factors — the mass of the bat and the speed of the swing — can raise batted ball speed (BBS), which adds distance to a hit. But swing speed can affect BBS more dramatically.

Posted by Orrin Judd at May 19, 2007 7:13 AM
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