Power: power is defined as the time rate of doing work. P =  = = = Fvcos. SI unit of power is watt = Nms-1

Laws of conservation of mechanical energy: It state that the total mechanical energy of a system remain constant if only conservative forces are acting on

Potential energy of spring: When a spring is compressed or elongated by a force F and the elongation or compression is x, then F x.

Conservative and non-conservative field:  A force is said to be conservative if the work done by or against the force in moving a body depends

Work energy theorem: Work done by all forces like conservative, non-conservative, external, internal acting on a particle is equal to the change in kinetic energy

Work done by static friction: When static friction is acting between body and the surface, then there is no relative displacement between body and surface.