We can safely ignore attractive forces if the thermal energy of the particles is
sufficient to ensure that all collisions are elastic. This is the billiard ball
model, and we shall make use of it to investigate the properties of
molecular events on a microscopic scale. We will further simplify our discussion
to one dimensional space, as none of the essential physics are lost by doing this.
All particles have thermal energy which is given by the equipartition theorem as
kT/2 for each axis. T is the absolute temperature and k is