A stream of gas molecules by a mass of m is incident on a wall. The collisions are elastic and the velocity of the molecules are v, and normal to the wall is vector i. Discover the pressure that is exerted on the wall by the molecules if a number N molecules strike the wall per unit time, and per unit area. The diagram is an i, j, favouring i to the left, with m in the third quadrant by velocity towards the origin at an arbitrary theta.