now I'm really fantastic at drawing this mechanical device, but you can imagine that dropping a weight can cause a paddle wheel to turn.

机械装置的时候,我真的很着迷，你可以想象,当重物掉落的时候会带动桨轮旋转。

麻省理工公开课 - 热力学与动力学课程节选

When we have just a single bond in them molecule, you have all the free rotation you want, you can just spin it around, there's nothing keeping it in place.

当我们在分子力只有一个单键时，你可以随意旋转，你可以让它转起来，没有什么东西能固定住它。

麻省理工公开课 - 化学原理课程节选

So, there is a way to go from the unprimed coordinates to the prime coordinate by rotating your axis and actually calculating the components.

现在我们有一种方法可以从原坐标系,转变到新坐标系,只要旋转坐标轴,并实际地计算一下坐标即可

耶鲁公开课 - 基础物理课程节选

So all that Bohr, for example, had to go on at this point was a more classical picture of the atom, as you can see on the left side of the screen there, which is the idea that the electrons orbiting the nucleus.

原子的经典图像，你们可以,看到屏幕左边，这是电子，绕着核子旋转，的概念,他已经知道。

麻省理工公开课 - 化学原理课程节选

So if we say that l is just talking about our kinetic energy part, our rotational kinetic energy, and we know that electrons have potential energy, then it makes sense that l, in fact, can never go higher than n.

如果我们说，l仅仅是,描述动能项，我们的旋转动能，我们知道，电子有势能，所以可以理解，l不能比n高。

麻省理工公开课 - 化学原理课程节选