来自《耶鲁大学开放课程：基础物理第9集第9集》

you've got to be very clear that

你必须清楚
the acceleration of that -- of parts --

部件的加速度
This is the saw blade, okay?

这是电锯刀片
I'm trying to draw for you

我试着画出来
one of these saw blades and it's spinning.

一个刀片在旋转
If you pick a point, say on the circumference,

如果你选择一点比如说圆周上的某点
you remember long back we learned,

记得我们很早之前学过
even if it's going at a constant speed,

即使它在以恒定的速度
a constant angular speed,

恒定的角速度在运动
it has a tangential velocity,

它都有一个切向速度
which is ω·R.

大小是 ω·R
And because of that,

因此