重力势能(gravitational potential energy)是物体因为重力作用而拥有的能量。物体在空间某点处的重力势能等于使物体从该点运动到参考点(即一特定水平面)时重力所作的功。重力势能的公式:Ep=mgh。
注意,这里,重力势能是增加的。
注意,重力势能,是减小的。
我先给你一个对于,重力势能的形式定义。
Let me first give you the formal definition of gravitational potential energy.
That is, you minimize potential energy and you see things falling under the force of gravity and so forthgoing to potential energy minima in conformance with this result.
换句话说,你使得势能最小化,然后发现我们关注的东西,在重力或者其他力的作用下下落,直到势能最小的地方,这和我们刚才的结果是一致的。
You might be winded doing it the second way, but when you get to the top and you are at the 60th story your gravitational potential is independent of how you got there.
对于走路你可能很抓狂,但你一旦到了顶层,你就是在第60层,你的重力势能,与你如何到达那里无关。
You know, if you want to measure the potential energy of something in a gravitational field, you have to define the zero somewhere, right, because it's arbitrary. You can set it anywhere you want. It's the same with enthalpy.
你知道,如果你想测量重力场,中某种东西的势能,你需要,在某处定义一个零点,对吧?,因为势能的值是任意的,你可以把它设定在。
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