what is the distance from earth's surface to a point above its surface where the acceleration due to fravity is 1/8th th

问题描述:

what is the distance from earth's surface to a point above its surface where the acceleration due to fravity is 1/8th that of the surface

很简单啊,万有引力公式:F=GMm/(R^2),所以地球表面的重力加速度是FM/(R^2),这里M是地球质量,R是地球半径.
设1/8的地方离地心距离是r,重力加速度是FM/(r^2)=1/8*FM/(R^2),所以r=2根号2R,也就是距离地面大约1.8倍地球半径的位置