Potential energy

Potential energy is given by
V = mgh
m = mass of the body.
h = height of that body.
g = acceleration due to gravity.

Kinetic energy

Kinetic energy of a moving body is given by following formula,

K.E. = 1/2 ( mv2 )

or K.E. = p2/2m

m = Mass of the moving body.
v = Velocity of that body.
p = Linear momentum of that particle.

Mechanical energy

The mechanical energy ( E ) of a body is given by,

E = K + V
E = 1/2 (mv2) + mgh

K = Kinetic energy of a body.
V = Potential energy.
m = mass of a body.
v = velocity of that body.
g = acceleration due to gravity.
h  =  height of a body.

What is the energy?

The capacity to do work is called energy.
Energy is a scalar quantity. The dimensional formula of the energy are the same as the dimensional formula of work i.e. [ M1L2T-2 ].
SI unit of energy is joule and CGS unit of energy is erg.

Characteristics of energy

  • The entire matter possesss energy.
  • Energy can neither be created nor be destroyed. The quantity of energy in the universe is constant
  • Energy can be transformed from one form to the other.