On Final Motions of a Chaplygin Ball on a Rough Plane

A heavy balanced nonhomogeneous ball moving on a rough horizontal plane is considered. The classical model of a "marble" body means a single point of contact, where sliding is impossible. We suggest that the contact forces be described by Coulomb's law and show that in the final motion there is no sliding. Another, relatively new, contact model is the "rubber" ball: there is no sliding and no spinning. We treat this situation by applying a local Coulomb law within a small contact area. It is proved that the final motion of a ball with such friction is the motion of the "rubber" ball.