  Some dynamical properties of non interacting particles in a bouncer model are
described. They move under gravity experiencing collisions with a moving
platform. The evolution to steady state is described in two cases for
dissipative dynamics with inelastic collisions: (i) for large initial energy;
(ii) for low initial energy. For (i) we prove an exponential decay while for
(ii) a power law marked by a changeover to the steady state is observed. A
relation for collisions and time is obtained and allows us to write relevant
observables as temperature and entropy as function of either number of
collisions and time.
