(a) Kicking a football. Here, the work done will be positive as the displacement of the football is in the direction of the applied force.

(b) When a object is being lifted in the upward direction. In this case, the force of gravity is acting in the downward direction and the displacement of the object is in the upward direction. As the angle between the force and displacement is 180°, the work done by the gravitational force on the object is negative. Work done by a force is negative if the applied force has a component in a direction opposite to the displacement.

(c)A boy pushing against a wall it does not move, d=0.Then work done is zero.