# Collision of two pool balls

1. Jan 17, 2008

### Bobolis

I have a bit of time on my hands at the moment and being an avid pool fan I wanted to try my hand at programming a pool simulation. Now I have the balls moving correctly whether they are sliding or rolling but I am having a little trouble getting my head round the collisions.

Ideally I want the collisions to be modelled taking into account the friction between balls and therefore use the conservation of angular momentum as well as the conservation of linear momentum. I have tried looking up everything I can on the subject but I can't seem to work out how to model it. Everywhere seems to talk about the collision force acting between the two balls but I can't seem to work out how I get this force. I realise that in reality this force happens over a period of time but for the sake of simplicity I wanted to program the collisions to be instantaneous. So what I am asking basically is how do I find out the force acting between these two balls? As it's a programming problem I ideally want this in terms of information that I can use, such as the balls linear and angular velocity. Hope that makes sense.

2. Jan 17, 2008

### Shooting Star

Before I try to give an answer to your main query, how are you slowing down the balls? Have you been able to give spins to the balls?

3. Jan 17, 2008

### Bobolis

Yeah, the motion of the balls is working fine with both linear and angular velocities. It calculates the change in position from it's previous state change (i.e. when a force is applied to it or when it changes from sliding to natural roll) as time elapses.

4. Jan 18, 2008

### Shooting Star

Last edited by a moderator: Apr 23, 2017
5. Jan 18, 2008

### Bobolis

Yes I have read that but unfortunately it does not deal with ball - ball friction.