初等物理的读者,在遇到质量与重量这两个物理量时,常常感到困惑不解;在运算过程中,也经常出现把这两个物理量混用的错误。如果要避免发生错误,就必须把二者的基本概念弄清楚。质量:要了解质量,就必须先了解什么叫做惯性。“一切物体在没有受到外力作用的时候(或这个物体在所受的合外力为零的时候),总保持速度不变的直线运动或静止的状态。”这就是牛顿第一定律(也称惯性定律)。物体保持原来运动状态的性质称为惯性。各个物体的惯性大小并不相等,如一列高速行驶中的火车,很不容易使它在很短的时间内停止下来;但是乒乓球运动员,只要轻轻挥动一下手中的球拍,就可把对方打来的乒乓球很快地 Elementary physics readers are often puzzled by the two physical quantities of mass and weight, and often mistakes in mixing these two quantities of physics. If you want to avoid mistakes, we must make clear the basic concepts of the two. Quality: To understand the quality, we must first understand what is called inertia. “All objects are always in a straight line at a constant speed or in a stationary state when they are not subjected to external forces (or when the resultant external force is zero).” This is Newton’s first law (also known as inertia law). The object to maintain the original state of motion is called inertia. Each object’s inertia size is not equal, such as a high-speed train, it is not easy to make it stop in a very short period of time; but table tennis players, just gently swipe their hands racket, you can hit the other party Table tennis is coming quickly