For example, no matter how much a dancer wishes to leap off the floor and then start turning, the law of conservation of angular momentum absolutely prevents such a movement.
例如，无论一个舞者多么想要跳离地板，然后开始旋转，角动量守恒定律绝对阻止这样的动作。
I add angular momentum in this direction and you see that here.
我在这个方向加入了角动量，你们可以在这看到。
When I do that, I apply, I add angular momentum in this direction.
当我这样做的的是，我将角动量,加到这个方向。
Angular momentum is pointing straight at me, away from you.
角动量直接指向我，远离你们的方向。
Angular momentum is now in this direction.
角动量现在是在这个方向。
Angular momentum is in this direction.
角动量是这个方向了。
Somehow, it has the smell of some conservation of angular momentum.
不知怎么的，这一定律和,角动量守恒定律有所相似。
In motions of rotation angular momentum appears in much the same way as linear momentum appears in motion of translation.
在旋转运动中的角动量产生的方式与平移运动中的线动量的产生是基本相似的。
The researchers calculated how this would affect the rotation rate of the whole planet, which would compensate to conserve angular momentum.
研究人员计算出这会怎样影响整个地球自转速度，这有助于保持角动量守恒。
So this was originally the spin angular momentum of the wheel.
所以，这是原本的旋转的，角动量。
What is the magnitude of that angular momentum?
角动量的，数值是多少？
The angular mo... the momentum of the cluster as a whole not angular momentum, I misspoke.
有角度的动。,星云整体的动量,不是有角度动量，口误。
The spin angular momentum is now in this direction, so I'm going to give it a torque like so.
旋转的角动量现在是这个,方向的，我给它一个这样的力。
And so the angular momentum of spin of the wheel is in this direction.
所以旋转的角动量是，这个方向。
Now we're going to apply for the first time in systems like this, the conservation of angular momentum.
这是我们第一次，在这种系统里使用，角动量守恒定律。
Angular momentum is conserved about this point Q, but only about that point Q.
角动量，在点Q守恒，也只有在点Q守恒。
Therefore there is a total angular momentum which is the vectorial sum of the two.
因此，总的角动量,有两个向量。
That means if there's torque, there's a change of angular momentum.
这意味着，如果那有一个力矩，就会有角动量的改变。
Spinning this direction, angular momentum is in this direction.
这个方向旋转，角动量是，这个方向。
It describes the angular momentum of the electron.
它描述的是，电子的叫角动量。
And now the angular momentum is rotating like this, is pointing here.
现在的角动量是像这样，转动的，指向这。
Why? Because it has angular momentum.
为什么，因为有了一个角动量。
I am the spin angular momentum.
我就是旋转的角动量。
We have here the spin angular momentum that you saw.
这有一个旋转的角动量,如你们所见。
You give it spin angular momentum, it becomes stable.
有了一个旋转的角动量，就变得稳定。
有了旋转的角动量。
So spin angular momentum has the property of stabilizing things.
旋转的角动量有，稳定事物的性质。
Look at that spin angular momentum.
观察那个旋转角动量。
Bohr expressed the quantum condition by the angular momentum, quantum condition in the following manner.
波尔阐明了他的量子理条件，通过角动量，和以下的量子条件进行量子化。
What will the spin angular momentum do?
旋转的角动量会怎样呢？
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