Types of Energy: Potential Energy and Kinetic Energy

All the different types of energy fall into two basic categories: Kinetic energy i.e. energy due to the motion of the object and Potential energy i.e. energy stored in a body.

• Kinetic energy is due to the object such as the motion of electrons, waves, atoms, substances, molecules, and objects.
• Potential energy is stored in an object due to its position.
• It can be stored in various forms and can never be destroyed.
• There are different types of energy such as chemical, thermal, nuclear, electrical, mechanical energy, and many more.
• Energy can be measured with various units and the SI unit of energy is Joule. 
• Apart from SI units of energy, there are other common units such as Calories, Horsepower, Kilowatts, Megawatt, and Barrel.

Key Terms: Potential energy, Kinetic energy, Gravitational Energy, Nuclear energy, Electrical energy, Chemical energy, Elastic potential energy, Radiant energy

Also Read: Thermodynamics

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Types of Energy

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Energy is defined as the ability to do work. Knowledge of the conversion of energy from one form to another and using it as work leads to the development of modern civilization.

• There are many forms of energy such as Heat energy, Light energy, Gravitational energy, Electrical energy, Chemical energy, etc.
• These forms of energy fall into two basic categories of energy: Kinetic Energy and Potential Energy.
• According to the law of conservation of energy, energy can neither be created nor be destroyed but it can be changed from one form to another.
• For example, the kinetic energy of water can be converted into electrical energy.

There are also many different sources of energy, but they fall into two categories:

• Renewable energy sources
• Nonrenewable energy sources

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Potential Energy

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Potential energy is the energy stored in an object due to its position, its electric charge, stresses within itself, or other factors. 

• Potential energy is associated with conservative forces.
• The work done by the conservative forces depends only on the initial and final positions of the body.
• An object's potential energy is found in its position, not in its motion.
• The elastic potential energy of a stretched spring, the electric potential energy of an electric charge, and the gravitational potential energy of an object are the common types of potential energy.
• SI unit of potential energy is joule (J).

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Types of Potential Energy

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The different types of potential energy are as follows:

Gravitational Energy

Gravitational energy is the energy stored in an object due to its height from the surface.

• It depends on the mass and height of the object from the surface.
• More gravitational energy is stored in an object if it is at a higher height and has heavier mass.
• When a bicycle rider moves down a steep hill, then the gravitational energy of the bicycle and rider converts into motion energy.
• A hydropower plant is also an example of gravitational energy in which the gravitational potential energy of stored water at a height is converted into kinetic energy when falls and then it is used to run a hydroelectric turbine to produce electricity.

The equation for the gravitational potential energy is

G_PE = m x g x h

Where,

• m is the mass of the object
• g is the acceleration due to gravity 
• h is the height of the object from the surface

Nuclear Energy

Nuclear energy is the potential energy of the particles such as protons and neutrons that are present inside the nucleus of an atom.

• This energy holds protons and neutrons together to form nuclei.
• Nuclear energy can be formed either by fusion or fission.
• Fission is the most widely used process for nuclear energy.
• The splitting of an atom leads to the release of particles and strikes with other Uranium atoms to splits them and this process of continuously splitting atoms is known as the chain reaction.
• The splitting of the atoms is generally controlled by control rods in a nuclear power plant and they are called the moderators. 

Elastic Potential Energy 

The energy accumulated as a result of applying a force in order to deform an elastic item is known as elastic potential energy.

• The energy is stored until the force is released, after which the item returns to its former shape, resuming its function.
• The object could be compressed, stretched, or twisted as a result of which it gets deformed.

Some of the common examples are:

• The stretch bow of an Archer.
• Bungee Cords
• Trampoline

  Elastic Potential Energy of a Metal Spring

Chemical Energy

Chemical power is the energy collected in a bond of an atom or molecule.

• Petroleum, Batteries, natural gas, petroleum, biomass, and coal are examples of chemical energy.
• Chemical energy is converted to thermal energy or heat energy by burning wood or burning gasoline in a car's engine.

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Kinetic Energy

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The kinetic energy of a body is the form of energy that it possesses due to the motion of the body. It is also defined as the work done in accelerating an object of a given mass from rest to its stated velocity.

• The motion of electrons, waves, atoms, substances, molecules, and objects are examples of kinetic energy.
• A system of bodies that is the combination of many individual bodies may have internal kinetic energy due to the motion of individual bodies.
• The SI unit of kinetic energy is joule (J).
• The kinetic energy of a body of mass m moving with velocity v is given by

K.E = 1/2 mv²

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Types of Kinetic Energy

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The different types of kinetic energy are as follows:

Electrical Energy 

The energy that gets carried by the electrons in motion in an electric conductor is known as electrical energy. The more electrical energy the charges carry, the faster they move.

• It is one of the most widely used types of energy.
• For example, electrical energy which is stored in coal is transformed into electricity by changing its form in a power plant, Lightning, Batteries, etc.

Sound Energy

Sound energy is a type of kinetic energy which produces due to vibrations of particles 

• This energy travels in the form of a longitudinal wave.
• The waves which have frequency ranges from 20 Hz to 2 kHz are audible to humans.
• Sound waves below 20 Hz frequency are called infrasonic and above 20kHz is called ultrasonic.
   

Thermal Energy

The energy contained within a system and produced by the movement of its molecules is known as thermal energy.

• Thermal energy is the component responsible for the temperature of the substance or system.
• Heat is the term for the transfer of thermal energy.

Radiant Energy

The energy that is transferred by electromagnetic radiation in the form of electromagnetic waves is called radiant energy. 

• Radiant energy is commonly used in the fields of solar energy, radiometry, lighting, and heating. 
• It is also used in the field of telecommunications.
• The sources of radiant energy include radio frequencies, gamma rays, x-rays, radio frequencies, microwaves, heat, and light.

Motion Energy

The energy of a moving object is known as Motion energy.

• The faster the body moves, the more the motion energy it contains.
• Blowing wind is an example of motion energy.

Also Read: 

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Things to Remember

• Energy can be defined as something as ‘the ability to do any work or the ability to apply a force that in turn causes an item to move from its original place’.In other terminology, we can say that energy is the force that causes objects to move.
• The standard unit of energy is Joule (J). A joule is the amount of energy expended when a force of one newton is applied over a one-meter displacement. 
• Kinetic energy and potential energy are two different types of energy. 
• According to the rule of conservation of energy, energy can only be transferred from one form to another as it cannot be destroyed or created.
• Kinetic Energy can be classified into sound, electrical, thermal, and radiant energy.
• Potential energy is classified into chemical energy, electrical energy, gravitational potential energy, nuclear potential energy, and elastic potential energy.