首先，我用了机械能，守恒定律-，这里没有摩擦力-，我会向你们展示，这，和功能定理完全一致，现在你会怎么做呢？

I used first the conservation - of mechanical energy — there was no friction — and then I showed you that it's completely consistent with the work-energy theorem, so what would you do now?

youdao

牛顿力学：牛顿第一、二、三定律，惯性和非惯性参考系，牛顿守恒定律，力和潜能，重力场，向心力，低频振荡。

Newtonian dynamics: first, second and third laws, inertial and non-inertial reference frames, conservation laws, forces and potentials, gravitational field, central forces, small oscillations.

youdao