These are physical knobs that are available us as experimentalists. And so when we turn these knobs on our system, we want to know how the enthalpy is changing for that system.

这些都是我们做实验可,以得到的物理变量,所以当我们在系统中,改变这些量的时候。

麻省理工公开课 - 热力学与动力学课程节选

So now we have this derivative, in terms of physical quantities, things that we can measure.

现在我们得到了这个导数,它可以用实验可测的与。

麻省理工公开课 - 热力学与动力学课程节选

What it means is if you'd release a rock at that location one second before with a certain speed that we can calculate, it would've ended up here with precisely the position and velocity it had at the beginning of our experiment.

它的意义在于,若在该处以特定速度抛出一个物体,这个速度可通过计算得到,一秒之后,物体会运动至我们设定的起点,并且速度为我们设定的初速度

耶鲁公开课 - 基础物理课程节选