He said, first, let it go a little distance, take the distance over time, that gives you the velocity now.

他说,首先,让它运动一小段距离,距离除以时间,你就能得到现在的速度

耶鲁公开课 - 基础物理课程节选

How long" can be used in a question and it refers to a length of time or a length of distance.

How long” 句型用于问句中，用来询问时间或距离的长短。

How long课堂 - SpeakingMax英语口语达人

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

But luckily for us, there's a classical equation of motion that will, in fact, describe how the electron and nucleus change position or change their radius as a function of time.

但幸运的是，有一个,经典方程描述了电子和核子,位置或者它们直接的距离是,如何随时间变化的。

麻省理工公开课 - 化学原理课程节选

It varies with the square of distance so it goes - in order to go twice as far it takes four times as long.

速度是与距离的平方正相关的--,如果要扩散两倍的距离要多花四倍的时间

耶鲁公开课 - 生物医学工程探索课程节选

So I was hoping to see more like 99% on this, but you do still have two more days before the exam.

我本来期待这道题的正确率能达到，99%，的，但毕竟你们距离考试还有两天的时间。

麻省理工公开课 - 化学原理课程节选

Here, in one second, it seems to have gone much further, so it's probably traveling faster.

在这一秒内,它似乎运动了更远的距离,所以这段时间它可能运动得更快

耶鲁公开课 - 基础物理课程节选

Of course, you have allowed it to move a finite distance in a finite time.

你是让它在有限的时间内移动有限的距离

耶鲁公开课 - 基础物理课程节选

Alright. So, since we have these terms defined, we know the frequency and the wavelength, it turns out we can also think about the speed of the wave, and specifically of a light wave, and speed and is just equal to the distance that's traveled divided by the time the elapsed.

好了，我们已经定义了，这些术语，我们知道了，频率和波长，现在可以来考虑,波的速度了，特别是光波的速度，速度等于它走过的距离,除以所用的时间，因为我们。

麻省理工公开课 - 化学原理课程节选

So, we can use Coulomb's force law to think and it does that, it tells us the force is a function of that distance. But what it does not tell us, which if we're trying to describe an atom we really want to know, is what happens to the distance as time passes?

来考虑这两个粒子之间的,它告诉我们力随距离的函数关系,但它不能告诉我们，而我们如果要描述,原子又非常想知道的是,距离随时间的变化时怎样的？

麻省理工公开课 - 化学原理课程节选

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