Escape velocity is simply the speed of an object that's shot out of a cannon the minimum initial speed so that the object could later escape Earth's gravity on its own.

逃逸速度就是一个物体的速度，比如说，从加农炮中射出的最小初始速度，这样这个物体以后就可以自己脱离地球的引力。

youdao

So to get into the center-of-mass frame, you must subtract the velocity of the center of mass from the initial velocities.

要进入重心体系，你就必须减去速度，重心的速度，从原始速度中减去。

youdao

Next, create your dynamic body, which has a position, initial linear velocity, and angle.

接下来，创建动态物体，它具有方位、初始线速度和角度。

youdao

Conversely, if I knew the velocity of this object, I also know what time it is, provided I knew the initial velocity.

反过来,如果我知道了这个物体的速度,我也同样可以知道时间,只要初速度是已知的

耶鲁公开课 - 基础物理课程节选

It's very interesting because velocity seems to require two different times to define it -- the initial time and the final time.

这非常有趣,因为速度似乎需要两个时间才能算出来,初时刻和末时刻

耶鲁公开课 - 基础物理课程节选

What that means is, if you know the velocity of the given time and you know the initial velocity, you know what time it is.

这个方程的意义是,如果你知道某个给定时刻的速度,并且知道初速度,你就能知道运动的时间

耶鲁公开课 - 基础物理课程节选

Update: The initial details are here, an initial analysis by our contributor Dan Frommer here, and more to follow on Velocity.

FORBES: HP To Acquire Palm For $1.2 Billion