物理规律揭示了物理现象的本质,它是在相关物理概念的基础上建立起来的物理量之间的联系,物理概念是理解物理现象的关键.物理规律或物理量之间的关系式往往是在一定条件下才成立的.在应用定义、定律、定理时一定要弄清它们的确切含义和适用条件,以免张冠李戴乱套公式.机械运动的定义是指物体相对于其他物体的位置变化,这里的“其他物体”就是指参考系(也就是我们认为静止不动的物体),也就是说参考系是为描述物体的运动情况而引入的一个概念.只有确定了参考系,才能准确地知道物体运动的规 The laws of physics reveal the nature of physical phenomena. They are the links between physical quantities established on the basis of related physical concepts. Physical concepts are the key to understanding physical phenomena. The relationship between physical laws or physical quantities is often under certain conditions. It is only when it is established that it is necessary to clarify the precise meanings and applicable conditions when applying definitions, laws, and theorems, so as not to inconvenience the formula. The definition of mechanical motion refers to the change in the position of an object relative to other objects. The object " refers to the reference system (that is, the object we think stands still), that is to say the reference system is a concept introduced to describe the movement of the object. Only when the reference system is defined, can we accurately know the motion of the object regulation