In
mechanics, the
virial theorem provides a general equation that relates the average over time of the total
kinetic energy,
![](http://info.babylon.com/onlinebox.cgi?rt=GetFile&uri=!!ARV6FUJ2JP&type=0&index=1235)
, of a stable system consisting of
N particles, bound by potential forces, with that of the total potential energy,
![](http://info.babylon.com/onlinebox.cgi?rt=GetFile&uri=!!ARV6FUJ2JP&type=0&index=4218)
, where angle brackets represent the average over time of the enclosed quantity. Mathematically, the
theorem states