文章针对新版人教版选择性必修一教材中的研究斜槽末端小球碰撞时的动量守恒实验装置，分入射小铁球与轨道槽底接触与不接触这两种情况，推导出小铁球在与槽端静止的小玻璃球碰撞后的边滚边滑运动后，其出水平槽口速度的相对增加量（相对于没有摩擦力的理想情形），以及由此给本动量守恒实验所带来的系统相对误差．理论计算结果均表明，这两者的数值均普遍较大，其中当入射小铁球与轨道槽底不接触时，这两者的数值更大．入射小铁球与轨道槽底不接触的实验误差结果与相应的理论误差结果大致吻合，两者均显示出新版教材上的这个实验装置确实存在较大的系统误差，建议替换为市场上在售的完整的碰撞实验器装置为宜，经测后者的实测相对误差仅在±2%以内．

The article focuses on the experimental setup for momentum conservation during the collision of two small balls at the end of an inclined groove in the latest version of the Peoples Education Press Selective Compulsory One textbook. It is divided into two cases: when the incident small iron ball contacts or does not contact the bottom of the track groove, and derives the relative increase in the velocity of the small iron ball exiting the horizontal groove after rolling and sliding motion after colliding with a small stationary glass ball at the groove end (relative to the ideal case without friction), as well as the system relative error for this momentum conservation experiment. Theoretical calculation results indicate that the values of both are generally large, with larger values observed when the incident small iron ball is not in contact with the bottom of the track groove. The experimental error results for the incident small iron ball not contacting the bottom of the track groove are roughly consistent with the corresponding theoretical error results, both of which show that there is indeed a significant systematic error in this experimental device in the latest version of the textbook. It is recommended to replace it with a complete collision experimental device available on the market, which has been tested to have a relative error of only ±2%.