Pressure is when you have one of these hard spheres colliding against the wall.

这是一个小球,它与墙发生碰撞。

麻省理工公开课 - 热力学与动力学课程节选

It is like an elastic collision between billiard balls.

就像是台球在，台球桌上发生弹性碰撞。

麻省理工公开课 - 固态化学导论课程节选

If the vehicle in the unfortunate circumstances of a collision, has to be able to maintain the security of the hydrogen which means more mass, which means a lot of the efficiency is being squandered What's the environmental impact of hydrogen production?

如果车辆,在碰撞中发生了不幸，要仍然能够保持氢气的安全性的话,意味着需要更多的质量，也就是说大部分效率被浪费了,制氢对环境有什么影响呢？

麻省理工公开课 - 固态化学导论课程节选