I am currently trying to model collisions of rigid balls. I have successfully been able to calculate collisions that only deal with linear momentum, but have run into trouble when I want to calculate angular momentum (e.g. when ballA glances the top of ballB, both balls should start spinning a little). The balls have a coefficient of friction as well. Although the collisions are inelastic, in my model, all translational kinetic energy that is lost to friction is turned into rotational kinetic energy. Is there anyway to calculate the resultant angular and linear momentums of each ball?