According to the work$-$energy theorem, the net work done on an object is equal to the change in its kinetic energy. The work done by a constant force is given by W $=$ Fdcos$,$ where F is the magnitude of the force, d is the magnitude of the displacement, and is the angle between the force and the displacement. The change in kinetic energy can be written as $$K$=(1/2)$mvf$2-(1/2)$mvi$2.$