动量被认为是“守恒的”，也就是说，动量一旦被建立，就一定会转移到其他地方。

Momentum is said to be "conserved", that is, once you build it up, it has to go somewhere.

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能量在其任何形式都是守恒的。

Energy is conserved in all of its forms.

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我们要再一次假定，动量是守恒的。

Again, we have to assume that momentum is conserved.

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This is the corollary. It's due to Clausius and it says the energy in the universe is conserved.

这是由克劳修斯得到的,这条结论说宇宙间总能量守恒。

麻省理工公开课 - 热力学与动力学课程节选

The notion of conservation is that there's ways to transform things such that some aspects of them change but others remain the same.

守恒是指物体某方面的特征,不会因为其他方面特征的改变,而有所改变

耶鲁公开课 - 心理学导论课程节选

We invoke Dalton's Law of molar proportions, we write it subject to conservation of mass.

我们援引了摩尔分数的道尔顿定律，要服从质量守恒定律。

麻省理工公开课 - 固态化学导论课程节选