Mass in special relativity detail by Oliver Heaviside (1889) and George Frederick Charles Searle (1897). So the electrostatic energy behaves as having some sort of electromagnetic mass formula_25, which can increase the normal mechanical mass of the bodies. Then, it was pointed out by Thomson and Searle that this electromagnetic mass also increases with velocity. This was further elaborated by Hendrik Lorentz (1899, 1904) in the framework of Lorentz ether theory. He defined mass as the ratio of force to acceleration, not as the ratio of momentum to velocity, so he needed to distinguish between the mass formula_26 parallel to the direction of motion
Thermal velocity Boltzmann constant, formula_2 is the temperature, and formula_3 is the mass of a particle, then we can write the different thermal velocities: If formula_4 is defined as the root mean square of the velocity in any one dimension (i.e. any single direction), then If formula_4 is defined as the mean of the magnitude of the velocity in any one dimension (i.e. any single direction), then If formula_4 is defined as the most probable speed, then If formula_4 is defined as the root mean square of the total velocity (in three dimensions), then If formula_4 is defined as the mean of