How does a backspin affect a shot?

Answer 1

A ball with backspin will bounce slightly more backwards when it hits the ground, or slightly more forwards if it hits a ceiling.

In Basketball, this makes the ball more likely to fall through the hoop if it hits the back of the rim, or more likely to bounce high (and possibly fall into the hoop) if it hits the front.

In tennis, this makes the ball bounce higher on a normal shot, making it slightly easier to hit. It can prevent a drop shot from going as far, also, making the player run further in order to catch it.

In Golf, the ball will bounce a shorter distance (or possible bounce backwards after a very high shot).