There are two mutually perpendicular forces acting on an object. One force acts in the direction of motion of the object and the direction of other force is perpendicular to the motion. During this interval, the kinetic energy of the body changes from 25 J to 100 J. The work done by the force acting perpendicular to the direction of the object is zero.
75 J
The force acting perpendicular to the direction of motion produces no displacement and so the work done by this force is zero. In the above question, the kinetic energy would increase only due to the force acting in the direction of motion or velocity of the object. The force acting perpendicular to the direction of motion doesn't contribute to the increase in kinetic energy and hence it does no work.