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Potential Energy Study Guide

In this article, we explore the concept of potential energy and its application. Potential energy can exist in different forms, such as gravitational potential energy and chemical potential energy.

Introduction

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Ever heard of the saying “the higher you climb, the harder you fall”? It’s literally true because the higher you go above the surface of the Earth, the more ‘potential energy’ you accumulate. The same idea is true for a bow and arrow- the further you pull back the string, the faster the arrow flies. So what is potential energy, and how do we understand this phenomenon? Let’s find out!

ENERGY

Before we go about grasping the concept of potential energy, we need to understand what ‘energy’ is and what it does. The definition of energy goes like this:

“Energy is the capacity to do work.”

If you miss your lunch, you won’t have the energy to play in the evening. Similarly, energy enables some form of ‘work’ to be done, such as moving an object from one place to another or changing its shape. Energy can be stored and released to do different types of work.

STORED ENERGY OR POTENTIAL ENERGY

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When you pull back on the string of a bow or climb up a flight of stairs, you are doing work against a potential. You need to put in the energy to bend the bow against its stiffness and put in the energy to move up the stairs against gravity. This energy is stored in the form of potential energy, which can be released at any moment.

Think of the last time you went on a hike and pushed a small boulder resting atop a hill. The boulder rolls off the slope picking up speed and finally coming to rest at the bottom. Where did all that energy come from? It was already stored in the boulder as potential energy because of the height at which it sat at rest.

TYPES OF POTENTIAL ENERGY

Now that we know the meaning of potential energy, we understand that it can be stored in different forms:

1. Gravitational Potential Energy

Gravitational potential energy is stored in objects as a function of their position above the surface of the Earth. The Potential energy formula, in this case, is expressed as (Pe) in Joules.

Pe=mgh

Here, m = mass of the object

h = height of the object above the ground

g = acceleration due to gravity @ 9.8 m/s2

With both the mass and gravitational acceleration remaining constant, it can be seen that potential energy depends directly on the height of the object.

2. Elastic Potential Energy

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This is the potential energy stored in a stretched elastic object.
Examples include a stretched bow and a twisted rubber band.
When you pull on the string of the bow, you are causing the bow to stretch and bend while storing potential energy.
As soon as you let go, the energy is transferred to the arrow to shoot it forward.

3. Chemical Potential Energy

This is the type of energy stored in the reactants of a chemical process. Examples include the energy stored inside a battery’s electrolytes and energy stored in the oxidizer and fuel of a firework.
When the chemical reaction takes place, this energy is released in the form of heat, light, and sound.

SUMMARY

Energy is the capacity to do work.
Potential energy is a type of energy that can be stored in objects
Energy stored in objects because of their elevation from the Earth is gravitational potential energy.
Energy stored in an object because of a change in its shape is called potential energy.

FAQs

Q. What are the types of potential energy?

The different potential energy examples include:

Gravitational potential energy
Elastic potential energy
Chemical potential energy
Electrical potential energy

Q. What is the potential energy dimensional formula?

The formula for gravitational potential energy is Pe (mgh)=Mass X acceleration due to gravity X height. The dimensional formula is (M1 L2 T-2)

Q. Give examples of potential energy.

The gravitational potential energy is stored in rocks on top of a mountain.
The gravitational potential energy is stored in the water of a power station reservoir.
The chemical potential energy is stored inside a battery.
The elastic potential energy is stored inside a stretched rubber band.
The chemical potential energy stored inside firecrackers.

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