This week,we will tell about a call to limit a widely used pain medicine.

VOA: special.2009.07.21

It's true for any gas, and if I remove this limit here, r t is equal to p v bar, I'm going to call that an ideal gas.

这样的气体被称作理想气体,这就是理想气体的性质，理想气体的涵义是什么？

麻省理工公开课 - 热力学与动力学课程节选

That limit will be some arrow we can call the velocity at the time and it will always be tangent to the curve.

那个极限也就是一个矢量,我们称之为瞬时速度,并且它总是和轨迹相切的

耶鲁公开课 - 基础物理课程节选