  Recent interest in the old problem of the motion of a coin spinning on a
tabletop has focused on mechanisms of dissipation of energy as the angle alpha
of the coin to the table decreases, while the angular velocity Omega of the
point of contact increases. Following a review of the general equations of
motion of a thin disk rolling without slipping on a horizontal surface, we
present results of simple experiment on the time dependence of the motion that
indicate the dominant dissipative power loss to be proportional to the Omega^2
up to and including the last observable cycle.
