Question

what are conservative and non conservative force ?

Answer 1

Forces that do not store energy are called nonconservative or dissipative forces. Friction is a nonconservative force, and there are others. Any friction-type force, like air resistance, is a nonconservative force. The energy that it removes from the system is no longer available to the system for kinetic energy.
A conservative force is a force with the property that the total work done in moving a particle between two points is independent of the taken path. ... When an object moves from one location to another, the force changes the potential energy of the object by an amount that does not depend on the path taken.