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Potential energy is a fundamental concept in physics that refers to the energy possessed by an object due to its position or condition. It is the stored energy that can be converted into other forms of energy and is associated with various physical systems. Understanding potential energy is crucial in analyzing the behavior of objects, systems, and natural phenomena.
Examples of potential energy
- A barbell lifted high above a weightlifter’s head possesses potential energy due to its vertical position above the ground.
- A drawn bow possesses potential energy due to its stretched position
Potential energy exists in different forms, and each form has its own specific formula for calculation.
Common types of potential energy:
- Gravitational Potential Energy: Gravitational potential energy arises from the position of an object within the Earth’s gravitational field. It depends on the object’s mass, the acceleration due to gravity, and its height relative to a reference point. For example, a raised object possesses gravitational potential energy, which can be converted into kinetic energy when it falls.
- Elastic Potential Energy: Elastic potential energy is associated with objects that can be stretched or compressed, such as springs or rubber bands. When an elastic object is deformed from its equilibrium position, it stores potential energy, which can be released to perform work. The amount of elastic potential energy depends on the stiffness of the object and the amount of deformation.
- Chemical Potential Energy: Chemical potential energy is related to the energy stored in chemical bonds. It is commonly found in fuel, food, and other substances. When chemical reactions occur, the stored chemical potential energy is converted into other forms, such as heat or mechanical energy.
Derivation of Formula of Gravitational Potential Energy:
Consider an object of mass ‘m’, placed at a height ‘h’. Then the force required to raise the object to height ‘h’ will be,
F = m x g
So, Work done against the gravity to raise the object up to certain height ‘h’ is given by
W=F x h
W=mgh
This work done on the object is stored in the object in the form of potential energy (PE).
W=PE=mgh
Unit of Potential Energy
The SI unit of potential energy is the Joule (J). The Joule is a derived unit of energy in the International System of Units (SI) and is defined as the amount of energy transferred when a force of one Newton acts on an object and displaces it by one meter in the direction of the force.
Since potential energy is a form of energy, it is measured in the same units as other forms of energy. The Joule is the standard unit for energy in the SI system, which includes potential energy along with other types such as kinetic energy and thermal energy.
Solved Examples of Potential Energy Formula
Example 1: A bouncy ball of mass 30kg is at a height of 10m above the ground. The gravity is equal to 𝟗. 𝟖𝒎/𝒔2. What is the potential energy of the ball?
Mass, m =30kg
Displacement, s =10m
Acceleration due to gravity = 9.8 𝑚/𝑠2
Potential energy
PE=mass x g x height
PE=30 x 9.8 x 10
PE=2940 Joules
Therefore, potential energy will be 2940 J.
Example 2: A roller coaster car with a mass of 500 kg is at the top of a hill, 30 meters above the ground. Calculate the potential energy of the roller coaster car.
Given:
Mass of the roller coaster car (m) = 500 kg
Height of the hill (h) = 30 m
Acceleration due to gravity (g) = 9.8 m/s²
Solution:
Potential Energy (PE) = m * g * h
PE = 500 kg * 9.8 m/s² * 30 m
PE = 147,000 Joules (J)
Therefore, the potential energy of the roller coaster car is 147,000 Joules (J).
Frequently asked questions on Potential Energy Formula
What is potential energy?
Potential energy is the energy possessed by an object or system due to its position, condition, or configuration. It represents the stored energy that can be converted into other forms of energy and is typically associated with the forces acting on the object or system.
What are the different types of potential energy?
There are several types of potential energy, including gravitational potential energy, elastic potential energy, chemical potential energy, electrical potential energy, and nuclear potential energy. Each type depends on different factors and has its own specific formula for calculation.
How is gravitational potential energy calculated?
Gravitational potential energy is calculated using the formula PE = m * g * h, where PE represents potential energy, m is the mass of the object, g is the acceleration due to gravity, and h is the height or vertical displacement of the object relative to a reference point.
What is the relationship between potential energy and kinetic energy?
Potential energy and kinetic energy are two forms of energy that are interconnected. Potential energy is converted into kinetic energy when an object or system undergoes motion. As an object falls, for example, its potential energy decreases while its kinetic energy increases. The total mechanical energy, which is the sum of potential and kinetic energy, remains constant in the absence of external forces.
How does potential energy affect an object's behaviour?
Potential energy influences an object's behaviour by determining how it will transform into other forms of energy. Objects with higher potential energy tend to have a greater ability to do work or cause changes in their surroundings. For example, a compressed spring has potential energy that can be released to perform mechanical work.
Can potential energy be negative?
In certain contexts, potential energy can be negative. This typically occurs when a reference point is chosen, and the potential energy is measured relative to that point. If an object is located below the chosen reference point, its potential energy can be negative.
