  A gravitational potential in the relativistic case is introduced as an
alternative to Wald's potential used by Verlinde, which reproduces the familiar
entropy/area relation S=A/4 (in the natural units) when Verlinde's idea is
applied to the black hole case. Upon using the equipartition rule, the correct
form of the Komar mass (energy) can also be obtained, which leads to the
Einstein equations. It is explicitly shown that our entropy formula agrees with
Verlinde's entropy variation formula in spherical cases. The stationary
space-times, especially the Kerr-Newman black hole, are then discussed, where
it is shown that the equipartition rule involves the reduced mass, instead of
the ADM mass, on the horizon of the black hole.
