This piston is being brought out, so we expect 0 the work to be negative, negative. And we start o V2 ut with zero volume. We end up with a volume p2 of V2, and the external pressure is constant to p2.

所以我们可以想象功是负的,开始的时候体积是,最终的容积是,外界的压力恒为。

麻省理工公开课 - 热力学与动力学课程节选

So you can imagine that adds real excitement and energy to the class and puts a little bit pressure on the professors to make sure that we have something worth coming half way around the world for.

可以想象,为课堂带去的兴奋和活力,也给教授施加了压力，我们要确保,能传授值得绕半个地球赶来学习的知识。

哈佛公开课 - 幸福课课程节选