Every sport has a machine that fires balls at players during practice, and they are not even close to evenly matched. One of them tops out at 80 mph. Another one doubles that. We counted down all four, and the winner is the sport where the ball is the smallest and the racket is the only thing standing between you and a 120 mph serve. If you want to learn more, check out @KiwiCo at kiwico.com/YTShorts #kiwico #science #sports