# Baseball meets tennis racketMarch 24, 2015 3:33 PM   Subscribe

Another question from the "things my 9-year-old asked me and Google can't find" file: what would happen if you tried to hit a major league fastball with a tennis racket? Would the ball rip through the strings? Or would you actually be able to hit the ball back with distance? Would you hurt yourself?
posted by escabeche to Sports, Hobbies, & Recreation (6 answers total) 3 users marked this as a favorite

Hmm. A baseball is 3x as massive as a tennis ball. The record serve is something like 150 mph. The average fastball is 90 mph. So to stop a fastball, it'd "only" need to exert double the force it needs to start a super strong serve, which doesn't seem that implausible. However, to return the pitch back at 90 mph, it'd take double that force, which is starting to sound like it's going to fail.
posted by aubilenon at 4:03 PM on March 24, 2015 [1 favorite]

The fastest baseball pitch was 169 kph and a baseball weighs 5 oz, giving that pitch a momentum of 6.65 m kg / s.
The fastest tennis serve was 263 kph and a tennis ball weighs 2 oz, giving that serve a momentum of 4.14 m kg / s.

These numbers are comparable enough that I would imagine a pro tennis player would be able to return a major league fastball, but not with any significant distance.
posted by contraption at 4:09 PM on March 24, 2015 [1 favorite]

When my child played little league, I used to hit fly balls to the outfielders using a tennis racket. After about 15 to 20, my elbow was throbbing. The stings would loosen too. I think it would depend on what grip was used (two-handed, forehand or backhand) if there would be much of a "return" and pain.
posted by 724A at 4:13 PM on March 24, 2015 [3 favorites]

A baseball bat is thicker than a tennis racket, yet they still splinter sometimes when they hit a baseball. So I'm not sure the handle of the tennis racket would make it.
posted by Hither at 6:27 PM on March 24, 2015

Racquets are available in carbon fiber, steel and aluminum, all potentially stronger than wood. And the strings have give reducing the impulse to the handle.
posted by Mitheral at 8:04 PM on March 24, 2015

A baseball bat is thicker than a tennis racket, yet they still splinter sometimes when they hit a baseball.

Usually when that happens, the bat is hitting the ball somewhere closer to the handle, rather than on the barrel.

I think the key to the question is determining the tension at which tennis racket strings fail, but that varies depending on the string material. So, you figure the max tension given the span across the racket and compare it to the force imparted by the baseball. I don't know how much a tennis racket weighs, but a baseball bat will typically weigh around 2 pounds, with most of the weight concentrated at the barrel, where it has the highest angular velocity and therefore greatest momentum - your sectional modulus for the bat is going to be much closer to the impact point of the ball than for a tennis racket.

I think rather than just figuring the record high speed pitch, you're going to need the average velocity of a hit baseball vs. the average velocity of a return serve in tennis, and I just don't expect that you could hit a ball as far with a tennis racket as with a baseball bat. I don't think a pitcher could stand at home plate and just throw a ball into the second deck of a baseball stadium, so I'd imagine the forces acting on a hit baseball would be greater than just accounting for the pitch velocity alone. Plus, a tennis ball absorbs some of the force of impact because it's rubber; a baseball has much less "give".
posted by LionIndex at 8:14 PM on March 24, 2015

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