We'll then look at the quantity, internal energy, which we define through the first law, and we think of it as a function of two variables T and V.

接下来我们考虑内能，这是由热力学第一定律定义的物理量，我们把它看作T和V的函数。

麻省理工公开课 - 热力学与动力学课程节选

But before you even do that, I want to define for you an important concept, which is the velocity at a given time, v .

但在这之前,我要给你们定义一个重要的概念,也就是给定时刻的瞬时速度v

耶鲁公开课 - 基础物理课程节选