Now, in physics we do believe very strongly in the conservation of energy, not necessarily in the conservation of kinetic energy.

在物理中我们并非坚信，能量是守恒的，这并不是一定的，动能不一定守恒。

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Then we have the conservation - of mechanical energy — the sum of kinetic energy and potential energy.

我们知道，机械能守恒定律-，动能和，势能的总和。

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The change in potential energy is going to be the change in kinetic energy You have conservation of energy principles.

势能的改变量，将会转化成动能的改变量，这就是能量守恒定律。

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