一、利用“重心”简化运动物体质心运动定理告诉我们:不管物体的质量如何分布,也不管外力作用在物体的什么位置上,质心的运动就像是物体的全部质量都集中于此,而且所有外力也都集中作用其上的一个质点的运动一样。如果物体的体积不太大,那么可认为物体处于均匀重力场中,则物体的重心与质心的位置是重合的。可见,一般情况下物体的运动都能等效为位于重心的质点的运动。例1.一名跳水运动员从离水面10m高的平台上向上跃起,举起双臂直体离开台面。此时其重心位于从手到脚全长的中点。跃 First, the use of “center of gravity ” to simplify the movement of objects mass center motion theorem tells us: no matter how the mass distribution of objects, regardless of external forces acting on the location of the object, the movement of the centroid is like the whole mass of the object are concentrated in this , And all external forces also concentrate on the movement of a particle above it. If the volume of the object is not too large then it can be assumed that the object is in a uniform gravitational field and the center of gravity of the object coincides with the position of the center of mass. Visible, under normal circumstances the object's movement can be equivalent to the focus of the particle movement. Example 1. A diver jumped up from a 10-m-high platform and lifted his arms straight out of the table. At this point its center of gravity is located mid-point from hand to foot full length. jump