Energy of a body is its capacity to do work" . for example , mechanical energy , heat and sound energies e.t.c. there are two basic form of mechanical energy. (1); kinetic energy. (2) ; potential energy (1); kinetic energy: the energy possessed by a body due to its motion is called kinetic energy. mathematically, k.E=1/2mv^2 .
(2) : potential energy: the energy possessed by a body due to its position is called potential energy.there are two types of potential energy, (I); Gravitational potential energy. (ii); Elastic potential energy. (I ); Gravitational potential energy; the energy possessed by a body because of its position in a force field e.g gravitational field. the potential energy due to gravitational field near the surface of earth at hight h is given by the formula, p.E=mgh . this is called gravitational potential energy.the gravitational potential energy is always determined relative to some arbitrary position which is assigned the value of zero P.E .in the present case this reference level is the surface of the earth as position of zero P.E .in some cases a point at infinity from the earth can also be chosen as zero reference level. Elastic potential energy: the energy stored in a compressed spring is the potential energy possessed by the spring due to its compressed or stretched state . this form of energy is called the elastic potential energy. Absolute potential energy: "the work done by the gravitational force in displacing the object from that position to infinity where the force of gravity becomes Zero, is called the absolute potential energy " .
