高中力学主要涉及的是质点力学,即研究对象一般都可视为质点.根据研究问题的复杂程度不同,可能是单一物体(质点),也可能是连接体(质点组).有时,我们还会研究质量连续分布的物体(以下简称连续介质),例如流体、刚体.怎样用质点力学方法去处理连续介质问题,尤其是怎样从连续介质中选取隔离体,这是教学中的难点.本文试通过几例来做一讨论. Mechanics of high school mainly deals with mechanics of matter, that is to say, the research object can generally be regarded as a particle, which may be a single object (particle) or a linker (particle group) according to the complexity of the research problem. It is difficult to teach how to use the mechanics of mechanics to deal with the problem of continuous media, especially how to choose the separator from the continuous media.This paper tried A few cases to do a discussion.