在“物体的运动”一章教学中,常会遇到有两运动物体的追赶问题,这类问题的研究方法较多,教学刊物上也有刊登,如“图象法”等.学生初接触时,感到较为棘手的原因在于这类问题中有两个研究对象.我们若能使其研究对象变为一个,则学生容易理解和掌握.通常所遇的追赶问题是已知甲、乙两物体的运动情况,问两物体能否相遇,何时能相遇,何时相距最远或最近等,具有相对性.教学时不妨用相对性原理,变二为一,效果理想. In the teaching of the “movement of objects” chapter, it is common to encounter the problem of catching up with two moving objects. There are many research methods for such problems and there are publications in teaching publications, such as “image method”. The reason for feeling more difficult is that there are two kinds of research objects in this type of problem. If we can make the object of our study into one, the students can easily understand and grasp. The usual catch-up problem is the movement of known objects A and B. Situation, asking whether the two objects can meet, when they can meet, when the farthest or the nearest, etc., have relativity. Teaching may wish to use the principle of relativity to change into two, the effect is ideal.