It wasn't the fact that they were running that time and they say "Oops! We are over the speed limit!

不是因为跑到那个时间,就说“不好，超过速度极限了！

哈佛公开课 - 幸福课课程节选

One way is to say, if I do a full revolution, I think of the speed as a distance over time.

一种方法是,如果我转完整的一圈,我认为速度就是距离除以时间

耶鲁公开课 - 基础物理课程节选

So, we can just plug it in. Speed is equal to the distance traveled, which is lambda over the time elapsed, which is 1 over nu. so, we can re-write that as speed is equal to lambda nu times nu, and it turns out typically this is reported in meters per second or nanometers per second.

经过的距离和所花的时间,我们把它们带进来,速度等于经过的距离,也即是lambda除以,所花的时间,通常它的单位,是米每秒或者纳米每秒。

麻省理工公开课 - 化学原理课程节选

Whenever you see a particle moving in a circle, even if it's at a constant speed, it has an acceleration, v square over r directed towards the center.

只要看到质点做圆周运动,即使是匀速圆周运动,也存在一个加速度,大小为 v^2 / r,方向指向圆心

耶鲁公开课 - 基础物理课程节选