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?

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？

youdao

And so you could have used the work-energy theorem or you can use the conservation of mechanical energy.

所以你也可以用，功能定理，或者是机械能，守恒定律。

youdao

Exactly the same idea, - and if you want to apply the work - energy theorem, of course, you will get exactly the same result.

完全一样，如果你想套用-，功能定理，会得到，完全相同的答案。

youdao