The core result of Galileo's inclined plane experiment is the proportion
relation between distance and
the square of time,but the local inhomogeneity of the dip angle and
friction coefficient leads to inhomogeneity of local
acceleration. In this paper,a simplified model including inhomogeneity of
the dip angle and friction coefficient
is introduced. Numerical results show that this inhomogeneity not only
induces random error but also leads to deviation
of the square relation between the distance and the time. It is further
found that if the dip angle keeps unchanged
and the friction coefficient decreases,the ball should change from non-slip
rolling to slip rolling,the deviation
degree of the square relation between the distance and the time would
increase rather than decrease. This result,
although contrary to intuition,coincides with the result achieved in some
corresponding researches on the history
of physics. These theoretical results are confirmed by our experiments. In
order to exclude the random factors in
releasing the ball,an equipment is designed to release the ball with zero
velocity. A more convenient method is also
carried out to measure the friction coefficient.