As it did, angular momentum became important.

随着它坍缩，角动变得重要起来。

That's called conservation of angular momentum.

这称为「角动守恒定律」。

But the original star's angular momentum is preserved.

但原始恒星角动被保留了下来。

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

最酷是它可以永久性地保持角动。

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

是个物理学家玩具可以示角动还有动能和势能。

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

由于角动不变，当距离增加时，速度就会减小。

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

更多角动意味着 她可转更多圈 ──在因摩擦力损失动，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.

以子涡旋为例，它基本上是超导体和超流体等材料中角动涡，使它们具有奇特性质。

And except for what's lost to friction, that angular momentum has to stay constant while the dancer is on pointe.

除了摩擦损耗动之外，当舞者踮起脚尖时 角动必须保持不变。

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，它可能不会保持恒定速度，但它角动会保持不变。

That's called the conservation of angular momentum.

- 这就是所谓角动守恒。

So the approach we chose to use is angular momentum.

所以我们选择使用方法是角动。

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

这是因为称为角动守恒原理。

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

基本上， 物体角动描述了它保持旋转趋势。

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

和线性动、角动一样 一直得救。

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使用快肌纤维，它们可以在不改变其净角动情况下摆动。

And that factor is angular momentum.

斜率，那个因素就是角动。

You can't create or destroy angular momentum. It always has to go somewhere.

你不能创造或破坏角动。 它总是必须去某个地方。

In physics, angular momentum describes something’s tendency to stay rotating once it’s started.

在物理学中， 角动描述了某物一旦开始就保持旋转趋势。

Some examples of vectors are displacement, velocity, acceleration, force, momentum, torque, angular momentum, and those are all vectors.

向一些例子是位移、速度、加速度、力、动、扭矩、角动, 这些都是向。