Comment on ‘Acceleration of a ball down an inclined plane’

Abstract Rod Cross ( Phys. Educ. 56 035017) has investigated the translational and angular accelerations of a rigid body rolling down a ramp inclined at angle Θ relative to the horizontal. The transition from rolling without slipping to rolling with slipping is explicitly included. Experimental results (obtained by digitizing movies of the motion of the object with reference lines drawn on it) are plotted as a function of Θ varying from 10° to 60° in 10° steps. In this Comment, the theoretical predictions for these accelerations are graphed over the continuous range of angles from 0° to 90°. The resulting curves have some features that are not visible in the experimental data.