## 质心与重心的区别(The difference between the center of mass and the center of gravity)

一般情况下，质心与重心的位置不重合。尺寸不十分大的物体放在重力场中，它上面各质元所在处的重力加速度g相同。这时物体的质量分布和物体的重力分布是一致的，物体的质心和重心位置重合。复杂物体重心位置可以由实验（悬挂法）测定，因此，利用质心与重心重合这一点也可以由实验测定复杂物体的质心位置。如果物体各处的重力加速度不同，则质心和重心不再重合，而且当物体或质点组与地球相距极远时，可以认为它们不再受重力，重心也就失去了意义，但是质心的概念却仍然有效。由此可见，质心的概念比重心的概念更具有普遍的意义。

In general, the center of mass does not coincide with the center of gravity.An object of less than a very large size is placed in a gravitational field, and the gravitational acceleration g at each of its prime elements is the same.The distribution of mass is the same as the distribution of gravity, and the center of mass and center of mass are the same.The position of the center of mass of a complex object can be determined experimentally (by the suspension method), so the position of the center of mass of a complex object can also be determined experimentally by the coincidence of the center of mass with the center of mass.If the gravitational acceleration varies from place to place, the center of mass and the center of gravity no longer coincide, and when the object or group of particles is at great distance from the earth, they are no longer subject to gravity, and the center of mass loses its meaning, but the concept of the center of mass remains valid.Thus, the concept of center of mass is more universal than the concept of center of gravity.