教后记徐万青牛顿第二定律是在实验基础上，通过抽象思维，运用数学工具总结出的客观规律。正因为这样，教学时我先从复习牛顿第一定律开始引出：ａ与Ｆ及ｍ间存在着一定的矛盾，它们之间既对立又统一。它们是如何统一起来的呢？由此引入新课。学生是第一次遇到用实验来研... The postscript to teach Xu Wanqing Newton’s second law is based on experiments, through abstract thinking, using mathematical tools to sum up the objective law. It is precisely because of this that when I was teaching, I first started by reviewing Newton’s first law: there is a certain contradiction between a and F and m, and they are both antagonistic and unitary. How are they unified? This introduces new lessons. The student is the first time encountered experimenting to...