Question

What happens to mechanical energy if only conservative forces act

Answer 1

Mechanical energy is the sum of the potential and kinetic energies in a system. The principle of the conservation of mechanical energy states that the total mechanical energy in a system (i.e., the sum of the potential plus kinetic energies) remains constant as long as the only forces acting are conservative forces.

Answer 2

conservative forces depends at the ends and mechanical energy depends on path therefore mechanical energy become zero as far as conservational forces are concerned and mechanical force is non conservational.