Starting with the virial theorem for an equilibrium configuration show that:
(a) the total kinetic energy of a finite gaseous configuration is equal to the total internal energy if $\gamma=C_p / C_v=5 / 3$, where $C_p$ and $C_v$ are the molar specific heats of the gas at constant pressure and at constant volume, respectively,
(b) the finite gaseous configuration can be in Newtonian gravitational equilibrium only if $C_p / C_v>4 / 3$.