So, the translational velocity of the center was equal to the radius, times the angular velocity.

因此，中心的速度将是 半径乘以角速度。

Because, to get its total velocity, you add the translational velocity to the tangential velocity.

因为要找到它的总速度，我们添加 过渡速度到切向速度。

Mainly, because at any given moment, the point at the bottom of the wheel doesn’t have a translational velocity.

主要是因为在任何给定时刻， 轮子底部的点都没有平移速度。

Mainly, because at any given moment, the point at the bottom of the wheel doesn't have a translational velocity.

这是因为在任何时候，在 轮底没有任何过渡速度。

We just saw that the translational velocity of the wheel is equal to the radius, times the angular velocity.

我们刚刚看到轮子的过渡运动 半径等于角速度。

Here’s the weird part: We just saw that the translational velocity of the wheel is equal to the radius, times the angular velocity.

这是奇怪的部分：我们刚刚看到轮子的平移速度等于半径乘以角速度。

But the bottom of the wheel won’t be moving at all … because its total velocity is its translational velocity minus the tangential, since they’re moving in opposite directions.

但是轮子的底部根本不会移动… … 因为它的总速度是它的平移速度减去切向速度， 因为它们在相反的方向上移动。