摩擦力既是进行物体受力分析的重点,又是力学计算的难点。许多学生在学习中由于弄不清静摩擦与滑动摩擦之间的联系与区别。常认为:摩擦力总是阻碍物体运动的,有摩擦力做功的物体系统其机械能一定减少……等等,以致阻碍了思维能力的培养和物理素质的提高。对此笔者精心设置问题,故布疑阵,引导对比分析,辨析错误是非,运用比较法,收到了比较好的效果。 1 比条件,认识共性首先让学生思考下述例题。 [例1] 两个相互接触的物体之间是否存在摩擦力,以下叙述中正确的是: A.两物体间没有相对运动,也可能有摩擦力。 B.只要两物体间有相对运动,就一定有摩擦力。 Friction is not only the focus of force analysis, but also the difficulty of mechanical calculation. Many students do not understand the connection and difference between static friction and sliding friction in their studies. It is often believed that: friction always hinders the movement of objects, and the mechanical energy of object systems with frictional power must be reduced...etc., which hinders the cultivation of thinking ability and the improvement of physical quality. The author carefully set up the problem, so the fabric of doubt, to guide the comparative analysis, to discriminate between right and wrong, using the comparative method, received better results. 1 than the conditions, understanding commonality first allow students to think about the following examples. [Example 1] Whether there are frictional forces between two objects in contact with each other, the following are correct in the following description: A. There is no relative movement between the two objects, and there may also be friction. B. As long as there is relative motion between the two objects, there must be friction.