机械能守恒定律是解决动力学问题的三件重要武器之一,它是一个标量关系,用它来处理只有保守力做功的物体运动的速率问题非常方便,这些是众所周知的。在教学中,遇到某种教辅书籍中的选择题有一选项,内容是“机械能守恒时,物体一定不受摩擦力和介质阻力作用”,对于这个选项的正误的判别,在同行中 The law of conservation of mechanical energy is one of the three important weapons for solving dynamic problems. It is a scalar relationship, and it is very convenient to use it to deal with the rate of movement of objects with only conservative forces. These are well known. In teaching, there is an option for a multiple-choice question in a supplementary book. The content is “When the mechanical energy is conserved, the object must not be affected by friction and medium resistance.” For the discrimination of this option, in the peer