How is inertia used in tennis?

Answer 1

Inertia is just a word for the fact that objects that are moving tend to stay moving until something hits it or stops its current manner of motion or its motion altogether. Having said that, ping pong might be the best example of this, as the ball does stay in motion until one of the two paddles hit it (starting with the serve, and each consecutive whack), which proves one of the laws of thermodynamics, but that is for another wikianswer.

Answer 2

inertia is the change of momentum momentum is force or speed of movement the harder you hit it, the farther the tennis ball will go. Of course, you don't want to hit the ball out of bounds but you also want to get it right over your opponet's reach with the racket (it's easy to move forward to hit a ball, but hard to move back to hit). So hitting the ball with the right momentum, you'll kick their rumps, lol