A student lifts an object in the upward direction. In doing so, he applies the force on the object in the upward direction and displaces it in that direction: (However, the force of gravity is also acting on the object.) (a) State the direction in which force of gravity is acting on it. (b) Which one of these forces is doing positive work? Give reason. (c) Which one of these forces is doing negative work? Give reason.
