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现行高中物理课本第三册(选修)里,关于“碰撞中的动量守恒”的学生实验中,要求用斜槽上滚下的入射球与放于斜槽水平末端前支柱上的轻质、等大的被碰球发生对心碰撞后均做平抛运动。该实验巧妙地用两球做平抛运动的飞行时间作为时间单位,使两球碰后瞬时的速度在数值上跟各自平抛运动的水平位移相等,从而简化了速度的测量,该实验也因此而变得简单易做。但是,实验结果却不理想,其原因是该实验中还存在人们所忽视了的隐患,即支柱的“障碍”作用。课本介绍的实验中,为使入射球飞离斜槽的瞬时刚好与被碰球发生对心碰撞,因此安放被碰球的
In the current high school physics textbook Book 3 (optional), student experiments on “conservation of momentum in collision” require the use of an incident ball rolling off a chute and light weight placed on the front pillar at the horizontal end of the chute. , And other large touched ball after the collision of the heart are doing flat throw. This experiment skillfully uses the flight time of the two balls as the flat throwing motion as the time unit, so that the instantaneous speed after the two balls hits is numerically equal to the horizontal displacement of the respective flat throwing motion, thereby simplifying the speed measurement. It becomes simple and easy to do. However, the experimental results are not ideal. The reason is that there are hidden dangers that people have overlooked, that is, the “obstacles” role of pillars. In the experiment described in the textbook, the ball that hit the ball was placed so that the instant that the incident ball flew away from the chute just happened to collide with the touched ball.