An ideal gas is inside a cylinder with a piston that can move freely. The walls of the cylinder and piston are non- conducting. The piston is being moved out of the cyl- inder at a constant speed u.
(a) Consider a gas molecule of mass m moving with speed `v (gt gt u)`. It hits the piston elastically at an angle of incidence q. Calculate the loss in kinetic energy of the molecule.
(b) If the area of piston is A and pressure of the gas is P, calculate the rate of decreases of molecular kinetic energy of the gas sample.
(c) If` u gt gt` molecular velocities, at what rate will the gas lose its molecular kinetic energy

Answer

(a) 2 mvu `cos theta` " " (b) Pau " " (c ) zero