一  万有引力和弹性力作功特点         (The features of the work done by the universal gravitational & the elastic force)
m’对m万有引力为
m移动dr时,F作元功为
1、万有引力作功                        (Work done by universal gravitational force)
m 从 A 到 B 过程中F作功：
2、弹性力作功           (Work done by elastic force)
弹性力