What is Potential Energy? | Formula and Examples

Unlike Kinetic Energy, which is the Energy of Motion. Potential energy is the energy of the rest of an object. It doesn’t depend on the motion of the object; it is decided by the position of the object. And it can be of any form like mechanical, electrical, chemical, nuclear or magnetic.

 

In this blog, we will study about the basic concept of Potential Energy. We will see the derivation formula and daily life examples of it.

 

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What is Potential Energy?

 

The word ‘Potential Energy’ was first introduced by the 19th century physicist, William Rankine. Though, the term potential can be traced from Aristotle's concept of potentiality. 

 

Potential energy is defined as the energy gained by the body by the work done by conservative forces. It can be represented at every point in the space between two vectors.

 

Potential energy is defined as the energy of the rest. It is the energy exhibited by the object due to its height and position. Potential energy can change it from one to another. It depends on the mass of the object and its position with the reference.

 

Different objects in a system will contain different potential relative to the position of the object with respect to the reference frame. The relative position plays an important role in determining the potential energy of the object. For consideration the spring has more potential energy when it is compressed or stretched as compared to its rest position. 

 

A ripe fruit has more potential energy when it is attached to the tree as compared to the position when it falls down. Unlike Kinetic energy, Potential Energy is not an individual characteristic and its properties depend on the entire system.

 

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Different Forms of Potential Energy

 

Potential energy can be classified into the following forms:

 

1. Gravitational Potential Energy

 

Gravitational potential energy is the energy an object contains due to height. For example, a book on the book shelf, a child at the top of a slide, etc.

 

2. Elastic Potential Energy

 

Elastic potential energy is energy of an object when it is stretched or compressed beyond its rest position. For example, a rubber band, a diver jumping from a diving board etc.

 

3. Chemical Potential Energy

 

Chemical potential energy is the energy released during a chemical reaction. It is the energy stored before the fusion of chemicals. For example, crackers, a charged battery, etc.

 

4. Electrical Potential Energy

 

Electrical potential energy is the energy that flows through the wires of electrical current. For example, solar cells, car headlights, etc.

 

5. Nuclear Potential Energy

 

Energy stored within the particles of the atoms. For example, energy transformed into nuclear fusion.

 

6. Magnetic Potential Energy

 

Magnetic potential energy is the energy stored because of attractive forces between two objects. For example, ball bearings, metal spoons, etc.

 

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How to Calculate Potential Energy?

 

Potential energy is represented as U in mathematical equations. The potential energy of an object can be calculated by different formulas depending upon the form of the potential energy. Here is the list of common formulas used to derive the potential energy.

 

The gravitational potential energy can be calculated using the formula,

 

U (gravitational) = mgh,

 

where m is the mass of the object, g is defined as acceleration due to gravity (approximately calculated as 9.8), and h is the distance or height of the object from the origin.

 

The potential energy of a linear spring is calculated using,

 

U (spring x) = ½ kx2,

 

where k is constant and x is the displacement covered by the spring.

 

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Examples of Potential Energy in Real-Life

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Real-life examples of potential energy

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Now to understand potential energy more clearly, let us consider the examples from day-to-day life.

 

1. Pendulum

 

Pendulums are attached to height objects from where they can easily swing. For example, a pendulum clock. As the pendulum is attached to a height, its posses’ potential energy. The maximum potential energy of the bob is when it is held to one end. 

 

But as the bob starts moving, its potential energy is slowly converted into Kinetic Energy. Again, when the bob reaches the highest point of the second end, it has high Potential Energy. The cycle continues again till the pendulum halts at a particular stop.

 

2. Spring

 

Spring contains Elastic Potential Energy. Elastic Potential Energy arises due to stretching and compression of the spring. Both compressed and stretched springs consist of some potential energy. 

 

Compressing a spring requires some amount of kinetic energy. But when the compressed spring is released, the stored potential energy is again converted into the Kinetic Energy.

 

3. Swimmers and Divers

 

Before diving in water, the swimmers first stand on a diving board and stretch themselves. Standing on the top of the diving board, gives the divers some gravitational potential energy. This potential energy is converted into kinetic energy, while the diver jumps off. 

 

High the height of the diving board, high the potential energy. And more will be converted to Kinetic Energy. Thus, professional swimmers choose high diving boards to get more Kinetic Energy at the end to cut the viscosity of the water.

 

4. Bow and Arrow

 

Bow and arrow following the first law of thermodynamics are great examples of potential energy. Before releasing the arrow, the archer pulls back the bowstring. 

 

This delivers some Potential Energy to it. When the bowstring is released, the potential energy stored is immediately transformed as the Kinetic Energy. With the newly kinetic energy attained, the bow moves forward.

 

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5. Water in Dams and Reservoirs

 

The water stored in dams and reservoirs possesses some amount of Potential Energy due to the height of the dam and reservoirs. We all know that the energy possessed by an object at rest is the potential energy. 

 

When the gates of dams open, the water which is resting down gains the motion, and the stored Potential Energy is transformed into the kinetic energy, hits the turbine and generates the Electricity.

 

6. Rock at the Mountain’s Edge

 

A rock standing on a cliff’s edge possesses potential energy. This energy is due to the height of the rock. Potential energy due to height is also known as gravitational potential energy. 

 

If someone pushes this rock, the stored potential energy is converted into the kinetic energy. Higher the height, higher the converted energy, and terrifying the outcomes of the rock when it falls down.

 

7. Snow

 

The snow-capped mountains which appear so peaceful to you, also possess some potential energy. The snow resting on the top of mountains has potential energy due to its position. 

 

When the potential energy stored in the snow is converted into kinetic energy, the snow slowly starts moving down from the mountains. This conversation of energy stated here takes place due to snow avalanche, after fresh snowfall breaks the packed snow cover.

 

8. Rubber Band

 

We all once have hurt the wrist of our friend, by stretching a rubber band from the opposite side. A stretched rubber band has some potential energy in it. 

 

The potential energy stored in a rubber band is due to the elasticity of the rubber band and is also known as elastic potential energy. As you release the stretched rubber band, the energy stored in it is converted into the kinetic energy and it transfers the same to the surface holding it.

 

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Despite these very examples, there are several other examples of potential energy around us. For consideration, a soccer ball, elastic coil, ripe fruit before it falls, river water at the top of the waterfall, a charged battery, explosives, solar cells, etc.

 

Energy is an important source for doing work. Everything around us possesses some energy in any form, maybe potential or kinetic, etc. Energy of a system is always conserved.