1. The problem statement, all variables and given/known data Revered members, A free particle is one which has no forces acting on it and since there is no forces acting on it, so there is no potential energy and E is entirely kinetic. 2. Relevant equations 3. The attempt at a solution My doubt is, when no forces act on a particle, it should remain at rest and possess potential energy only and Kinetic energy should be zero. How the converse happens here?