define conservative and non conservative forces of energy?

A conservative force is a force with the property that the work done in moving a particle between two points is independent of the path taken. Equivalently, if a particle travels in a closed loop, the net work done (the sum of the force acting along the path multiplied by the distance travelled) by a conservative force is zero.

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.

If you move a particle from A to B, by following different trajectories and you still get the same WORK, then the force is CONSERVATIVE. When the work is trajectory dependent the force is NON-CONSERVATIVE.

Remember the formal definition of work is



Work depends on the trajectory.