That would that would give rise to a perpetual motion machine, breaking of the second law. It can't happen.

否则就会使,得永动机出现，打破第二定律那是不可能的。

麻省理工公开课 - 热力学与动力学课程节选

You see an object in motion, you find a and you give a a certain numerical value, 10 meters per second squared.

你看到一个物体在运动,你会发现它的 a,然后给 a 赋值,10 米每秒平方

耶鲁公开课 - 基础物理课程节选