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.

Rod Cross ( Phys. Educ. 56 035017) 研究了从相对于水平面以θ角倾斜的斜坡滚下的刚体的平移和角加速度。明确包括从无滑动滚动到有滑动滚动的过渡。实验结果（通过数字化对象运动的电影并在其上绘制参考线获得）绘制为Θ的函数，从 10 到 60，分 10 步变化。在本评论中，这些加速度的理论预测是在从 0 到 90 度的连续角度范围内绘制的。所得曲线具有一些在实验数据中不可见的特征。