简易变质量系统的牛顿第二定律

Newton's Second Law for the Simple Change Mass System

在建立变质量系统运动微分方程过程中，一般都采用冲量、动量原理，涉及到△m△v这一项的忽略问题，这往往便教者及学生感到疑惑，本文给出一种不需要“忽略”的方法。

In the course of setting up the moving differential equation of the simplechange mass system,people usually adopt impulse and momentum principles. This would dealwith the neglecting problem of the △m△v term,and it often makes teachers and students feelpuzzled. This paper tries to offer a mothod without 'neglecting'.