It's a physics toy that demonstrates angular momentum, potential energy, and kinetic energy.

是个物理学家的玩具可以演示量还有能和势能。

As it did, angular momentum became important.

随着的坍，量变得重要起来。

That's called conservation of angular momentum.

这称为「量守恒定律」。

What's neat is that they can maintain angular momentum indefinitely.

最酷的是可以永久性地保持量。

Since the angular momentum doesn't change, when the distance increases the velocity has to decrease.

由于量不变，当距离增加时，速度就会小。

More angular momentum means she can make more turns before needing to replenish what was lost to friction.

更多的量意味着 她可转更多圈 ──在因摩擦力损失量，需再补充之前。

Take quantum vortices, which are basically whirlpools of angular momentum in materials like superconductors and superfluids, giving them strange properties.

以量子旋为例，基本上是超导体和超流体等材料中量的漩，们具有奇特的性质。

Well, as a planet orbits the Sun it may not keep a constant speed but it does maintain its angular momentum.

当行星绕太阳运行时，可能不会保持恒定的速度，但的量会保持不变。

By bending in the middle and using fast twitch muscle fibers, they can whip around without ever changing their net angular momentum.

透过在身体中断弯曲并用快肌纤维，们可以在不改变其净量的情况下摆。

But the original star's angular momentum is preserved.

但原星体的量得以保留。

That's called the conservation of angular momentum.

- 这就是所谓的量守恒。

It has lots of angular momentum  which causes it to spin.

具有大量的量，这其旋转。

This is because of a principle called conservation of angular momentum.

这是因为称为量守恒的原理。

Basically, an object’s angular momentum describes its tendency to stay rotating.

基本上， 物体的量描述了保持旋转的趋势。

And we could use photo gates to measure its change in angular momentum.

我们可以用光电门来测量其量的变化。

So their rotation speed slows down to compensate and keep their angular momentum the same.

因此们的旋转速度慢以补偿并保持们的量相同。

In other words, when did the moon acquire the exact angular momentum that it has now?

换句话说，月球是什么时候获得了现在所具有的精确量的？

Because angular momentum must be conserved.

因为量必须守恒。

And, like linear momentum, angular momentum is always conserved.

和线性量、量一样 一直得救。

Yeah, you have to get more angular momentum, like more orbital inner momentum to not fall in.

是的，你需要更多的量，就像更多的轨道内能，这样才不会掉进去。