For , the RMS velocity is or We can compute the expected value of the kinetic energy. This is what we expect from the Virial theorem. Jim Branson 2013-04-22 ... Feb 11, 2009 · A current of 1400 A exists in a rectangular copper bus bar of dimensions 0.6 cm by 9 cm. The current is due to free electrons moving through the bus bar at an average velocity of v m/s. The concentration of free electrons is 10^29 electrons/m^3 and they are uniformly dispersed throughout the bus bar. What is the average velocity of an electron?