A cubic vessel (with faces horizontal + vertical) contains an ideal gas at NTP. The vessel is being carried by a rocket which is moving at a speed of 500 m/s in the vertical direction. The pressure of the gas inside the vessel as observed by us on the ground

a) remains the same because 500 m/s is very much smaller than v_rms of the gas

b) remains the same because the motion of the vessel as a whole does not affect the relative motion of the gas molecules and the walls

c) will increase by a factor equal to
 where v_rms was the original mean square velocity of the gas

d) will be the difference on the top wall and bottom wall of the vessel

Answer:

The correct option is b) remains the same because the motion of the vessel as a whole does not affect the relative motion of the gas molecules and the walls.

EXPLANATION:

As PV = nRT, P remains unaffected as n, R, T and V.

Because the temperature of the tank remains constant, the pressure remains constant as well.
Let’s talk about what’s going on inside the ship now. The gas molecules continue to collide with one other and with the confining vessel’s wall. These collisions are completely pliable. In the gas, the number of collisions per unit volume remains constant. Because the motion of the vessel as a whole has no effect on the relative motion of the gas molecules with regard to the walls, the pressure inside the vessel remains constant.