Consider a gas with density ρ and cˉ as the root mean square velocity of its molecules contained in a volume. If the system moves as a whole with velocity v , then the pressure exerted by the gas is:
a. 31ρcˉ2
b. 31ρ(cˉ+v)2
c. 31ρ(cˉ−v)2
d. 31ρ(cˉ2−v2)