Potential Energy

Potential energy is the energy stored of position by an object. It is a type of energy that can be converted to other forms and related to some attractive or pushing forces.

Figure 1

Types of potential energy include: gravitational potential energy, elastic potential energy, chemical potential energy, electrical potential energy and nuclear energy.

Gravitational Potential Energy

Gravitational potential energy is the energy in an object as the result of its vertical position or height. The energy is stored in the gravitational attraction of the Earth for the object. There is a straight relation between gravitational potential energy and the mass of an object. Extra massive objects have greater gravitational potential energy. Also, the higher that an object is, the greater the gravitational potential energy. This can be expressed in the formula: PE = mgh. Where PE is the energy (in Joules), m is the mass (in kilograms), g is the gravitational acceleration of the earth (9.8 m/sec^2) and h is the height above earth’s surface (in meters).

Figure 2

Elastic Potential Energy

The energy stored in elastic materials as the product of stretching or compressing. Elastic potential energy can be stored in bungee chords, trampolines, springs, rubber bands, an arrow drawn into a bow. The quantity of elastic potential energy in a device is associated to the amount of stretch of the device, which means the more stretch it has, the more stored energy.

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Elastic potential energy is related to Hooke’s Law which states that the force needed to extend the spring will be directly proportional to the amount of stretch or extension.

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Chemical Potential Energy

The energy in the chemical bonds of matter. The bonds have chemical potential energy which is out when they are broken and the substance experience a chemical reaction. In this processes, conservation of mass is maintained. Bonds are broken and changed but the amount of matter remains the same. Common example of this principle is in a combustion reaction within the engine of the car. Chemical potential energy that was stored is then released and the car is set in motion. Yet, conservation of mass still happens as the mass of the gasoline and oxygen.

Electrical Potential Energy

Two types of this potential energy are: Electrostatic Potential Energy which is the energy of an electrically charged particle at rest in an electric field. Electrodynamic Potential Energy also known as magnetic potential energy which is defined as charged particles have magnetic field

Nuclear potential energy

The potential energy of the particles inside an atomic nucleus.
Sample Problem:
A cart is full with a brick and pulled at constant speed along an inclined plane to the height of a seat-top. Given a mass of the loaded cart which is