The Physics of Baseball

Last week when I was watching the Cubs game with some friends, someone mentioned that it was nearly a physical impossibility for batters actually to hit a baseball, given how fast pitchers throw and how little time the batter has to decide whether or not to swing. I did some searching tonight, and it's true: hitting a major league fastball is nearly impossible.

I found a lot of other interesting facts, including a graphical timeline of the path the ball takes from the pitcher's hand to the bat. (I found that image from a page full of great links, most of which I haven't had time to look at.) Quantifying everything makes the feat of hitting the ball seem especially impressive:

The batter has about 0.5 seconds to gauge the path of a pitch, and the bat must be at the right place [within about 1 cm] at the right time [within 0.01 seconds] to make solid contact.  The bat-ball collision lasts typically for 0.001 seconds, and the average force on this ball is of order 10,000 Newtons, corresponding to a mass of about 1000 kg [or a ton].

Some of the facts I found really do seem unbelievable, such as this description of how the bat and ball distort on contact:

The batter exerts some 6000-8000 pounds of force on the ball. This force is required to change a 5 1/8th ounce ball from a speed of 90 mph to a speed of 110 mph. This distorts the baseball to half its original diameter and the bat is compressed one fiftieth of it's size.

Half its original diameter? I don't know if I buy that, but at least reading statistics like this makes me feel marginally better about the obscene salaries that top-notch players get.