ABSTRACT
Definition 6 Let the ideal orientation be defined as the orientation where the rod is parallel to the surface and the center of mass is below the rod.
Lem m a 7 We can always increase the rod’s kinetic energy after a bounce by allowing it to rotate around the center of mass afor free” (i.e., without using energy) to the ideal orientation (ignoring penetrations of the surface) and then letting it continue to fall while maintaining this orientation. However, if the rod is already in the ideal orientation after the bounce, its ki netic energy cannot be increased.
