Chapter WORK, POWER AND ENERGY Physics Study 1st Year Karachi Board And Punjab Board - FULL NOTES

Chapter WORK, POWER AND ENERGY Law of Conservation of Energy
Statement
Energy can neither be created nor be destroyed, however, it can be
transformed from one form to another .
Explanation
According to this law energy may change its form within the system
but we cannot get one form of energy without spending some other
form of energy. A loss in one form of energy is accompanied by an
increase in other forms of energy. The total energy remains
constant.
Proof
For the verification of this law in case of mechanical energy
(Kinetic and potential energy). Let us consider a body of mass 'm'
placed at a point P which is at a height 'h' from the surface of the
earth. We find total energy at point P, point O and point Q. Point Q
is at a distance of (h-x) from the surface of earth.