A particle of mass m is moving in a horizontal circle of radius r under a centripetal force equal to -k/r2, where k is a constant. The total energy of the particle is

Centripetal force, F=mv2r=−kr2Negative sign shows that the force is directed towards the centre of the circle.∴ mv2=kr K.E. =12mv2=k/2r P.E. =−k/r∴  Total energy =k2r−kr=−k2r