Statement-1 : Friction is non-conservation force.
Statement-2 : This is because work done against friction, in moving a body over a closed path, is never zero.

Work done by friction on a body moving on plain ground ……………

The work done by a body against friction always results in

The work done by a body against friction always results in

For perfect rolling motion, work done against friction is zero.

For perfect rolling motion, work done against friction is zero.

For perfect rolling motion, work done against friction is zero.

Statement-1:Comets move around the sun in elliptical orbits, the gravitational force on the comet due to sun is not normal to the comet's velocity, but the work done by the gravitational force over every complete orbit of the comet is zero. Statement-2: Gravitational force is a conservative force and the work done by a conservative force over a closed path is always zero.