Let's compare the Momentum Principle and the Angular Momentum Principle in a simple situation. Consider a mass m falling near the Earth (see figure below). Neglecting air resistance, the Momentum Principle gives dpy/dt = ?mg, yielding dvy/dt = ?g (nonrelativistic). Choose a location A off to the side, on the ground. Apply the Angular Momentum Principle to find an algebraic expression for the rate of change of angular momentum of the mass about location A. (Assume +x is to the right, +y is upward, and +z is out of the page. Use the following as necessary: m, g for the acceleration due to gravity, r for the distance from location A to the center of mass, and x for the perpendicular level arm distance from location A to the center of mass.)
