So what we do is we pick an origin, call it zero, we put some markers there to measure distance, and we say this guy is sitting at 1,2,3,4,5.

我们现在选择一个原点,称其为零点,我们做一些标记来测量距离,这个点在五个单位长度的地方

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