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What is Energy – Resources of Energy

Aug 19, 2022
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Introduction to Energy

Key Concepts

  1. What is energy
  2. Why do we need energy
  3. When can we say that an object has the energy?

introductionIntroduction

What is energy? 

Have you ever thought about what happens in the street light when it glows, what makes vehicles move, musical system when it has songs playing? 

In street light, it is light energy. In vehicles, it is mechanical energy, and in the sound system, it is sound energy. 

Energy is standard in all these situations.  

types of energy

biosphereExplanation

But what is energy? 

Definition: In physics, energy is regarded as the capacity to do work. In general, energy is the utility of the body to do some work like moving, heating, etc. 

Energy is represented by E, and the unit of the energy is Joules in the SI system. 

parallel

Energy resources: 

  1. Renewable energy 
  1. Non-renewable energy 

Renewable energy  

Renewable energy is sometimes called ‘clean’ energy, it is from nature, and it is ‘on-depleting’ and can be used again and again. 

E.g., Solar energy, tidal energy and wind energy 

Non-renewable energy: 

The energy which is not used again and again and depletes once used are called a non-renewable energy source. 

E.g., Coal, petroleum and natural gas 

Why do we need energy? 

Situation: 

Let us consider a restaurant which serves food to its customers daily. The restaurant makes food to meet the need of the customers. 

parallel

Can you say what type of energy they need to prepare food for the customers? 

energy in cooking

Can you list out various forms of energy resources that are used by the restaurant to meet its needs?  

restaurant

The restaurant needs: 

  1. Light energy to prepare food as they cannot prepare food in the dark. 
  1. The heat energy to prepare food in time. 
  1. Muscular energy to prepare raw materials and another service. 
  1. The electric energy for the working of the machinery. 
restaurant energy

We need energy: 

We all need the energy to do our daily works without interruption. Everything on the earth possesses energy; hence, all the objects on the earth have some energy or wants at some point to do work. 

sun

Energy is not only on the Earth but in space also. Every object has energy. 

E.g., Earth rotates around the Sun due to the energy and the light and heat from the Sun reaching the Earth from space. 

When can we say that a body has the energy? 

We can say that a body has energy when there is a useful work outcome. 

Energy is regarded as the capacity to do work. 

hard work

Example: 

Let us consider a block lying on the floor. The block is at rest and not moving in any direction. We can say that the block has no energy as the block is not doing any work. It is at rest. 

book at rest

Now, person A is moving the block from one place to another place, where the person needs to have the energy to move the block from one place to another. 

book moving

Therefore, we can say that the block and person A both possess energy as the person is using the energy to move the block from one place to another as useful work. 

Summary:

What is energy?

Definition: In physics, energy is regarded as the capacity to do work. In general, energy is the utility of the body to do some work like moving, heating, etc.

Energy is represented by E, and the unit of the energy is Joules in the SI system.

We need energy:

We all need the energy to do our daily works without interruption. Everything on the Earth possesses energy. Hence, all the objects on the Earth have some energy or want some energy to do work.

  • Energy is not only on the Earth but in space also.
  • Every object has energy.
    When can we say that a body has the energy? We can say that a body has energy when there is a useful work outcome.
  • Energy is regarded as the capacity to do work.

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