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Potential and Kinetic Energy Explained

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Overview

Energy can neither be created nor destroyed, this is the conservation of energy law. However, energy can be altered from one form to another.

All forms of energy are either potential or kinetic energy. Potential refers to stored energy while kinetic is energy in motion.

All energy, whether potential or kinetic, is measured in Joules (J).

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Potential Energy

Potential Energy is defined as the energy stored by a body by virtue of its position relative to others, stresses within itself, electric charge, and other factors.

When you (or a rock) are standing at the top of a hill, you possess more potential energy than when standing at the bottom. This is because your position relative to the Earth’s center of gravity can exert potential energy upon you to bring you closer to that center.

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Types of Potential Energy

Chemical

Every animate and inanimate object is the result of chemical reactions. Chemicals in a battery have the potential to be converted into motion, therefore they have chemical potential energy.

Elastic

Elastic potential energy is present when the object, such as a spring, is in a deformed state but can return to a static state. This means the spring has elastic potential energy when it is either stretched or compressed.

Nuclear

The mass of an atom’s nucleus is almost entirely comprised of its protons and neutrons. The force binding them together is considered potential energy because it causes them to weigh less than the sum of their parts.

Gravitational

An object’s relative location to a gravitational field is the gravitational potential an object has to do work. Earth’s gravity will pull a ripe apple from the branch and convert it into gravitational kinetic energy.

Kinetic Energy

Kinetic Energy is defined as energy that a body possesses by virtue of being in motion.

As you walk down stairs, as water boils, and as the planets orbit the sun, kinetic energy is being utilized.

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Types of Kinetic Energy

Mechanical

We already know kinetic energy is exerted when an object is in motion. When the gears are turning within an engine they are exhibiting mechanical kinetic energy.

Electrical

Electrical kinetic energy actually explains the transit of the electrical energy itself, electricity. For example, the electrical current that carries the charge from a battery to the light bulb is kinetic energy.

Thermal

Thermal energy is the result of an object’s temperature being changed. Heat, or thermal energy, can be transferred by convection, conduction, and radiation. When water boils, thermal energy is transferred by conduction as molecules vibrate.

Magnetic

Magnetic fields are the effect of electric currents and magnetic materials specified by the direction and strength of attraction or repulsion. The earth’s magnetic field is how the compass rose can determine North from South.

Kinetic And Potential Energy Working Together

All forms of kinetic energy are the result of a previous state of potential energy. For example, the stored chemical potential energy of a battery converts to electrical kinetic energy to transport electricity to a light bulb, which radiates thermal kinetic energy.

Electricity exchanged between red battery and green light bulb with red and green circles in the background.