本刊1994年第2期和1995年第3期曾刊登过有关超重、失重实验的演示实例.本人在多年的教学中,根据“简单、明了、尺寸大”演示教具的选择原则,采用如图1所示的“圆形测力计”来演示,现象明显,效果较好.牛顿第二定律的应用——“超重和失重”问题的演示实验与产生原因的分析进行如下设计.问题1;如何用测力计称出物体的重力? In the 2nd issue of 1994 and the 3rd issue of 1995, there were examples of demonstrations of experiments on overweight and weightlessness. In my teaching for many years, according to the principle of “simple, clear, and large” presentation teaching aids, we used The “circular dynamometer” shown in Fig. 1 demonstrates that the phenomenon is obvious and the effect is good. The demonstration of the application of Newton’s second law, “overweight and weightlessness”, and the analysis of the causes are as follows. Question 1; How to use a dynamometer to weigh the weight of an object?