The energy possessed by a body due to its position or deformation is called the potential energy, It is denoted by U. A compressed spring, a bent bow, a stretched rubber band, water in a dam etc. obtain potential force.
The potential energy is of two forms they are, gravitational potential energy and the elastic potential energy. Potential energy =weight x height.Potential EnergyGravitational potential energy:The energy possessed by a body by virtue of its position above the ground is called the gravitational potential energy. For calculation of gravitational potential zero, the ground is chosen as a reference level for zero potential energy.
When we take a body from ground to a certain height, the work done by external force against gravity is stored as the gravitational potential energy.The examples of gravitational potential energy are energy possesses by a stone at the roof of a building and energy possessed by water in a dam.Elastic potential energy:The energy possessed by a body due to its deformed state is called the elastic potential energy.The work required to deform a body from its normal position is stored in the form of elastic potential energy.
For example if a spring is stretched or compressed, some work is done against the restoring force. This work is stored as elastic potential energy. The stretched or compressed spring, a bent bow, the wound spring of a watch etc. own elastic potential energy.Potential Energy HeightUnit of potential energy:As potential energy is defined in terms of work, it has same unit as that of work. Therefore, in SI system the unit of potential energy is joule.
Formula for potential energy:Let a body of mass m be placed at height h above the ground level.Then, potential energy of body = Work done against gravity in raising the body through height h= External force (F) x Distance (h)But external force="weight" of bodyTherefore, Potential energy="Weight" x height = mg x h="mgh"The potential energy (mgh) is due to work done against gravity; hence it is called gravitational potential energy.Therefore, Height `h=(U)/(mg)`