In physics, matter is considered to possess two kinds of energies – kinetic or potential energy. Kinetic energy is defined as the energy an object displays or possesses because of some kind of motion or action. Potential energy, on the other hand, is the energy an object possesses or displays by virtue of its state of rest.

While potential energy is non-related to the environment of the object, kinetic energy is completely relative to the other moving or stationary objects in the environment. If an object is moving in an environment where other objects are moving too, the acceleration of the object will not be evident at all.

For example, a bullet going past a standing person has kinetic energy in the reference frame of the person but has zero kinetic energy in the reference frame of a train moving alongside. There are exceptions to this reference frame though.

The word ‘kinetic’ comes from the Greek word ‘kinesis’ meaning motion. The word ‘potential’ to define energy was coined by Scottish physicist William Rankine in the 19th century. Kinetic energy can also be passed from one moving object to another when a collision or contact takes place. This is not the case in potential energy.

Potential energy is also known as ‘restoring energy’ as it tends to force an object to return to its original state of rest. Potential energy works against any displacement force so, for example, when an object is lifted, it tries to return to its original state of rest through the gravitational force. The energy that the object possessed while moving was kinetic energy and once the object returns to its state of rest, the energy is transformed into potential energy.

Since energy cannot be destroyed or created, the conversion of energy from kinetic to potential and vice versa is the basis of the functioning of the universe.