I'm looking to simulate a bouncing and spinning ball in two dimensions. I have the detection working fine but I'm having a little difficulty with the physics. I have a moving ball colliding with a stationary immovable wall. I would like to know the resultant velocities of the ball in terms of: initial velocity u, initial angular velocity ω, radius r, coefficient of friction μ coefficient of restitution e, mass m, moment of intertia I obviously first we resolve normally to the plane. we have vj = -e*uj so the impulse = m(1+e)uj now I think there should be a rotational impulse proportional to this by a factor of the coefficient of friction, so ω increases by μm(1+e)uj/I but I get stuck here. I havent considered the initial angular velocity of the ball and its impact on the resultant velocity and resultant angular velocity. I hope someone can be of help, thanks a lot, Giles.