Potenatial Kinetics

In physics, energy is a quantity that can be assigned to every particle, object, and system of objects as a consequence of the state of that particle, object or system of objects. Different forms of energy include kinetic, potential, thermal, gravitational, sound, elastic, light, and electromagnetic energy. The forms of energy are often named after a related force. German physicist Hermann von Helmholtz established that all forms of energy are equivalent - energy in one form can disappear but the same amount of energy will appear in another form. Energy is subject to a conservation law. Energy is a scalar physical quantity. In the International System of Units (SI), energy is measured in joules, but in some fields other units such as kilowatt-hours and kilocalories are also used.

Potential energy

The potential energy of a body is the energy stored in the body by virtue of its position or the state of strain. Hence water stored in a reservoir, a wound spring, compressed air, stretched rubber chord, etc, possess potential energy.

Potential energy is given by the amount of work done by the force acting on the body, when the body moves from its given position to some other position.

Kinetic energy

The kinetic energy of a body is the energy possessed by the body by virtue of its motion. It is measured by the amount of work that the body can perform against the impressed forces before it comes to rest. A falling body, a bullet fired from a rifle, a swinging pendulum, etc. possess kinetic energy.

A body is capable of doing work if it moves, but in the process of doing work its velocity gradually decreases. The amount of work that can be done depends both on the magnitude of the velocity and the mass of the body. A heavy bullet will penetrate a wooden plank deeper than a light bullet of equal size moving with equal velocity.