The fact that when you go in a circle, you accelerate is what we're learning here, coming from the fact that velocity is a vector and its change can be due to change in the magnitude or change in direction.

而当你做圆周运动时你也在加速,这是我们在这里所学到的,原因就在于,速度是一个矢量,其变化可以通过改变模长,或者方向来实现

耶鲁公开课 - 基础物理课程节选

So, actually I want you to go ahead in your notes and circle that zero point and write "not a node."

在你们笔记上把这个零点圈出来,在旁边写上“不是节点“,它不是节点“

麻省理工公开课 - 化学原理课程节选