# Potential Energy

If a system has the capacity to do the work then it possesses energy. Work is the transfer of energy from one system to another system. This is a scalar quantity which is conserved in the isolated system according to the conservation of energy law. It is the basic concept of science. There are various forms of energy. Mainly it is classified into kinetic and potential energy.

When a ball is thrown then its potential energy is converted into kinetic energy. The kinetic energy is related to the motion of molecules while the potential energy shows the position of molecules or objects.

What is Potential Energy?

It is defined as the energy stored in an object. Potential energy can be divided into many types; Gravitational Potential Energy, Electric Potential Energy, Elastic Potential Energy etc.

Gravitational Potential Energy: It is define as the energy possessed by an object by virtue of its position relative to others.

Elastic Potential Energy: It is defined as the energy possessed by virtue of stresses within its body.

Electrical Potential: It is defined as the energy possessed by an object by virtue of the total charge stored within.

An Energy acquired by an object by virtue of its position is called its “Potential Energy”.

Potential Energy Formula: Consider an object of mass ‘m’, raised through a height ‘h’ above the earth’s surface. The work done against gravity gets stored in the object as its Potential Energy (Gravitational Potential Energy).

Therefore,

Potential Energy = Work done in raising the object through a height “h”.

Consider an object of mass ‘m’, raised through a height ‘h’, then its Potential energy is given by: Potential Energy = F x H … (1)

Where,

F = Force,

h = height attained due to its displacement.

But, F = mg (Newton’s Second Law of Motion)

Substituting for F in equation (1) we get,

Potential Energy (P.E) = mgH

The above relation is called Potential Energy Equation. From this, it is clear that the Potential Energy of an object depends on the height from the ground.

Examples of Potential Energy:

• Hydro Electric Power Plant: Water is stored in a dam at a considerable height and a particular quantum is allowed gravity flow to create a kinetic energy. This kinetic energy is converted as rotational energy of an electric generator by proper coupling. Finally, the Rotational energy is converted into electrical energy.
• Nuclear Power Plant: The Nuclear energy released from nuclear potential energies are used both for productive and destructive uses. Generation of power is a positive use. This concept is used in nuclear power plants throughout the world. On the other hand use of nuclear potential energy as a weapon like nuclear bombs.
• Spring in the Form of Elastic Potential Energy: The Springs on a vehicle act as cushion absorbing the shocks they are subjected due to road conditions. The force of shocks are absorbed by the springs in the form of elastic potential energy. Electric potential energy is also used as the source of power in electric motors.
• To Get Electric Power: The Chemical potential energy of fuels is used in generation of heat in boilers which in turn is used in generation of electric power.

Real life Example: We all know that dams are constructed on rivers for the generation of electricity. But do you know the reason behind this. Here, the potential energy possessed by water is used to harness electrical energy. Water raised to a certain height gains potential energy with respect to the ground due to the gravitational force acting on it. This energy is used to turn the blades of turbines positioned in the dams that eventually helps in the generation of electricity.

How to find the Potential Energy?

Example: A ball of mass 0.8 kg is dragged in the upward direction on an inclined plane. Calculate the total Potential Energy gained by this ball given that the height of the wedge is 0.2m?

Solution: It is given that mass of the object (m) = 0.8 kg

Since, the Potential Energy of the object is only dependent on its height from the reference position, we can say that,

P.E = mgh

P.E = 0.8 x 10 x 0.2

P.E = 1.6 J