"Within that week with support, of the body weight support, we were able to get him to stand without any help at the legs so he was generating enough force to bear his body weight."

VOA: special.2011.06.01

The force, as this weight drops is constant, mgh and so the work is just going to be m g h, h where this is h.

当重物掉落时候的力是恒定的，因此做功就是，这段长度是。

麻省理工公开课 - 热力学与动力学课程节选