# 2D Collisions

1. Nov 6, 2009

### MTK

I am trying to find a way to calculate a collision of two objects with rotation. I only managed to find two explanations on the internet, and even they didn't consider friction.

I do know these things that may be helpful:

velocity vectors of the objects
velocity vectors of the colliding point on the objects
surface normal and tangent
angular velocities of the objects
masses of the objects
elasticities of the objects
frictions of the objects

Is there a formula that can tell me the post-collision linear and angular velocities of the objects from this information?

2. Nov 6, 2009

### KLoux

Search for "Conservation of Momentum" and "Conservation of Angular Momentum" - you should be able to find some explanations and examples.

-Kerry

3. Nov 7, 2009

### MTK

I figured it out by this website (Link)

The only problem is that it does not account for friction.

4. Nov 8, 2009

### KLoux

What do you mean, it doesn't account for friction? Where is it that you are expecting friction to come into play? Can you give an example?

Typically, this type of problem involves considering the system just before and just after impact, so if there is friction between the two bodies and the surface they are sliding on, for example, that has no influence on the collision. It may influence the speeds at which they come into contact and the distances that they travel after the impact, however.

-Kerry

5. Nov 9, 2009

### A.T.

Without friction between the balls, no angular momentum (spin) will be transfered.