Give an example of negative work.

(N/A) Negative work occurs when the force applied is in the opposite direction to the displacement of the object. An example is the work done by the force of friction on a moving object. As the object moves in one direction,the frictional force acts in the opposite direction,resulting in an angle of $180^{\circ}$ between the force and displacement,which makes the work done negative $(W = F \cdot s \cdot \cos(180^{\circ}) = -Fs)$.