relative speed

基本解释

We are seated in one of the trains, and with us we have a special speedometer that measures their relative speed.
我们坐在其中的一列火车上带着特制的速度测量仪，可以测出两列火车之间的相对速度。
You are wrong because all that we know is that the relative speed between the two trains changed from 0 mph to 10 mph.
你之所以是错了，我们所知道的仅仅是这两辆火车之间的相对速度由每小时0英里增加到了每小时10英里。
A laser sensor mounted on the rear-view mirror constantly measures that relative speed with the vehicle ahead, ordering the brakes to apply pressure in the event that driver fails to do so.
汽车的后视镜上安装了一个激光传感器，它始终测量着汽车与前车的相对速度，如果在驾驶员在必要时未进行刹车操作，系统就会自动制动。

In hedge funds, he sees a growing interest in relative speed.
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