I am trying to recreate the [Slime Volleyball game](http://slime.tuxfamily.org/); however I am unsure how to go about implementing the physics of the ball movement.

The game consists of a circular ball and semi circle players that hit the ball over a net and against a wall. The ball cannot touch the floor.

I need to understand how exactly to implement the hitting of the ball against the player and what the physics entails.

I have already implemented gravity with a bouncing ball.

It is hard to find information related to implementing such physics from a game development perspective and I only have vague ideas about change in momentum from googling. If anyone could explain how to do so, I would greatly appreciate it.