And so going to the center-of-masssystem, you can always immediately calculate what the maximum heat is that you can expect from a collision.
现在看质量重心体系，你可以很快计算出，最大的热量是多少，你可以从碰撞中得到的。
2
The centerofmass of a system is defined as follows: I have here some kind of an object not just a point mass, but it has a finite size.
系统的重心,是这样定义的：,我有一个物体,不是有棱角的物体，但它大小有限。
3
In the absence of any net external forces - on a system as a whole — - as we discussed last time — the centerofmass will always have the same velocity.