We examine the dynamics of cylinders that are grooved to form N teeth
for rolling motion down an inclined plane. The grooved cylinders are e
xperimentally found to reach a terminal velocity. This result can be e
xplained by the inclusion of inelastic processes which occur whenever
a tooth hits the surface. The fraction of the angular velocity that is
lost during an inelastic collision is phenomenologically found to be
proportional to 2 sin(2) pi/N-alpha sin(3) pi/N, and the method of lea
st squares is used to find the constant alpha = 0.98. The adjusted the
oretical results for the time of rolling as well as for terminal veloc
ity are found to be in good agreement with the experimental results. (
C) 1998 American Association of Physics Teachers.