Law of conservation of mechanical energy
“The total mechanical energy of a system is constant, if the internal forces doing work on it are conservative and the external forces do no work”.
Verification:
Law of conservation of energy in case of freely falling body.
Let a body of mass ‘m’ falls from a height ‘h’ above the ground as shown in figure.
When the body is at the point A:
Initial velocity V0 is zero
When the body is at point B :
Suppose at point B, the body has velocity VB
When the body is at point C :
Suppose at point C, the body has velocity VC
From equations (1), (2), & (3) the total mechanical energy of the body at any point is constant.
Hence, the law of conservation of energy is verified in case of freely falling body.