Assuming that the door is relatively thin, the moment of inertia will be the same as that of a rod rotating about an axis at its end. If the mass of the door is 10 kg and its width is 1.5 m, find the angular acceleration of the door after applying a 50 N pushing force (about 10 lbs) at a) 1 m from the hinge, compared to b) 20 cm from the hinge.