我给它一定速度，第一辆车获得速度。

I get a certain velocity, which I put into the first car.

youdao

辅以精确计时进而获得速度信息。

The velocity is acquired by accurate timing.

youdao

但是随之而来的，在获得速度和效率的同时我们也付出了代价。

But as with everything else in life, this newly acquired speed and efficiency comes at a cost.

youdao

First, free velocity, constant velocity can be obtained for free without doing anything.

首先,速度是无偿的,恒定速度不需外力作用就能无偿获得

耶鲁公开课 - 基础物理课程节选