It knows that this particle happened to have a height of 15, at the time of 0, and a velocity of 10, and it is falling under gravity with an acceleration of -10.

这个质点恰好处在高度为15的地方,零时刻,初速为10,并在重力作用下以-10的加速度下坠

耶鲁公开课 - 基础物理课程节选

So, we just talked about the force law to describe the interaction between a proton and an electron. You told me that when the distance went to infinity, the force went to zero. What happens instead when the distance goes to zero? What happens to the force?

我们刚刚讨论了描述质子,和电子之间相互作用力的定律,当距离变为无穷时,力变为零，那当距离变为,零时会发生什么？,这时候力是多少？

麻省理工公开课 - 化学原理课程节选