a. Perfectly elastic collisions with the walls of their container.

i. Explain what is meant by a perfectly elastic collision.

ii. State three other assumptions of the kinetic theory.

b. A single molecule is contained within a cubical box of side length 0.30 m.

The molecule, of mass 2.4 × 10⁻²⁶ kg, moves backwards and forwards parallel to one side of the box with a speed of 400 m s⁻¹. It collides elastically with one of the faces of the box, face P.

i. Calculate the change in momentum each time the molecule hits face P.

ii. Calculate the number of collisions made by the molecule in 1.0 s with face P.

iii. Calculate the mean force exerted by the molecule on face P.