Give an example of a situation in which an applied force does not result in a change in kinetic energy.

(N/A) When a charged particle moves in a circular path under a uniform normal magnetic field,the magnetic force acts as a centripetal force directed towards the center,while the velocity of the particle is tangential to the path.
Since the force is always perpendicular to the displacement (velocity),the work done by the magnetic force is zero $(W = \vec{F} \cdot \vec{d} = 0)$.
According to the work-energy theorem,the change in kinetic energy $(\Delta K)$ is equal to the work done.
Since the work done is zero,the change in kinetic energy is also zero $(\Delta K = 0)$,meaning the speed of the particle remains constant.