The second piece of information we need to know is what actually the kinetic energy is of the ejected electron, and that's something we can just measure by measuring its velocity.

其次，我们需要知道的信息是,出射电子的动能，这可以通过,测量它们的速度得到。

麻省理工公开课 - 化学原理课程节选

NO So that the more complete answer to the question is that no, we're never going to be able to observe that because of the uncertainty principle it's not possible to observe a velocity that's this slow for a macroscopic object.

所以这个问题的完整答案是，由于不确定性原理,我们不可能测量到这么慢的,宏观物体的速度，希望这个解释。

麻省理工公开课 - 化学原理课程节选

A clock tells you what time it is, but you can also say what time it is by seeing how fast the particle is moving because you know it started with some speed.

时钟能告诉你现在的时间,但你也可以通过测量质点速度,来判断当前的时间,因为你知道它的初速度

耶鲁公开课 - 基础物理课程节选