Now I want to continue a case whereby I have a completely elastic collision.

我要继续此例，我有一个完全弹性碰撞。

youdao

I will often call it a completely elastic collision, which is really not necessary.

我常叫它完全弹性碰撞，但其实并不需要这样叫。

youdao

I told you I chose the case of - a completely elastic collision — Q and so kinetic energy must be conserved.

我说我选择这个例子，它是完全弹性碰撞-，为0,Q, is, zero——，那么动能必然守恒。

youdao