He says changing the mechanicalkineticenergy into electrical energy is easy.
他说,机械动能转化为电能是非常容易的。
2
Kineticenergy can be converted back to potential energy, can be converted back, - but the sum of them — which we call "mechanical energy" — is conserved.
动能可以转化,成为势能,也可以转化为动能,但是总和-,我们叫做的,机械能,是恒定的。
3
Then we have the conservation - of mechanicalenergy — the sum of kinetic energy and potential energy.