# Similarities Between Work and Energy

Imagine you’re pushing a heavy suitcase across the floor. You’re using energy to do this, like when you eat food to stay active. Work is the result of applying this energy to move something. Work and energy are two closely related concepts, and they go hand in hand. In a way, work and energy are like a team that makes the world go around. They help us understand how things happen and how we can make them happen.

While there are differences between work and energy, they are closely related concepts. In this article, however, we’ll discuss their commonalities instead. Without further ado, let’s talk about the similarities between work and energy.

## What is Work?

In physics, work is a fundamental concept that measures the transfer of energy when a force is applied to move an object over a distance. It’s like the bridge between force and motion. Work is all about using force to make things happen, whether it’s lifting, pushing, or any other action where energy is transferred to achieve a result.

For example, when you push a car, you exert force to move the car, and you’re doing work. The car gains kinetic energy as it starts rolling. This is precisely how engines work: by applying a force to move something, usually a vehicle, and converting energy into motion.

W = F.d.cos(θ)

W = work done (measured in joules)

F = magnitude of the force applied (measured in Newtons)

d = the distance over which the force is applied (measured in meters)

θ = the angle between the direction of the force and the direction of motion (cosine of the angle)

## What is Energy?

Energy is the ability to do work, make things happen, or cause changes in the world around us. Energy comes in various forms, like kinetic energy (associated with motion), potential energy (stored energy, like a stretched spring), thermal energy (heat), and more. From powering our homes to propelling rockets into space, energy keeps the world turning.

For instance, when you swing on a swing set, you have potential energy at the highest point, which then transforms into kinetic energy as you descend. At the bottom of the swing, all that kinetic energy turns back into potential energy. This cycle continues until you stop swinging.

KE = 1/2.m.v²

KE = kinetic energy (measured in joules)

m = mass of the object (measured in kilograms)

v = velocity (measured in meters per second)

PE = m.g.h

PE = potential energy (measured in joules)

m = mass of the object

g = acceleration due to gravity (approximately 9.81 m/s²)

h = height above a reference point (measured in meters)

## Similarities between Work and Energy

### Transfer of Energy

Both work and energy involve the transfer of energy. When work is done on an object, energy is transferred to or from it. For example, when you lift a book, energy is transferred to the book in the form of potential energy. When you drop it, that potential energy converts to kinetic energy.

### Common Unit of Measurement

Work and energy are both measured in the same unit, joules (J). Another common unit of measurement is the kilowatt hour (kwh). This means that the work done on an object or the energy it possesses can be numerically expressed in the same measurement, allowing for easy comparison and calculation.

### Direction of Force

In both work and energy calculations, the direction of the force applied is crucial. When you apply a force at an angle to an object’s motion, only the component of the force in the direction of motion does work, and this aligns with the concept of energy transfer. They are closely related. When you perform work on an object, you alter its energy state. This relationship between work and energy is fundamental in physics.

### Interdependence

Work and energy are interrelated concepts. Work done on an object changes its energy state. For instance, when you accelerate a car, you’re doing work, and as a result, its kinetic energy increases. On the flip side, when you use the brakes to slow down the car, kinetic energy drops. This illustrates how they both describe the same physical phenomenon from different angles.

## Summary

Work and energy are interconnected concepts in physics. Work is the transfer of energy when a force is applied to move an object over a distance. They share several key similarities: both involve the transfer of energy, are measured in joules, depend on the direction of force, and are interdependent. When work is done on an object, its energy changes. This fundamental relationship between work and energy is crucial to understanding how objects move and how energy is transferred and transformed in the physical world.

## FAQs

### Why are work and energy equal?

Work and energy are equal because of the principle of conservation of energy. This principle states that the total energy in a closed system remains constant; it can change from one form to another, but the total amount remains unchanged.

### Are work and energy always the same?

Work and energy are not always the same. Work is a measure of the transfer of energy between objects or within an object due to applied forces. Energy, on the other hand, is a property of a system that can take various forms, such as kinetic energy, potential energy, thermal energy, etc.

### What is the relationship between work and energy formula?

The relationship between work and energy can be understood through the work-energy theorem. It states that the work done on an object is equal to the change in its kinetic energy.

This relationship is expressed by the formula: Wnet = ΔKE

Here, Wnet represents net work, and ΔKE represents the change in kinetic energy. This theorem helps us connect the concepts of work and energy, showing that when work is done on an object, it results in a change in its kinetic energy.

### References :

+ “Work and Energy.” Byju’s, byjus.com/physics/work-and-energy/#principle%20of%20work%20and%20energy.

+ “Work and Energy.” CliffsNotes, www.cliffsnotes.com/study-guides/physics/classical-mechanics/work-and-energy.

+ Hibbeler, R.C. Engineering Mechanics: Dynamics. Pearson Education India, 2007.

+ Nardo, Don. Kinetic Energy: The Energy of Motion. Capstone, 2007.

+ Image credit: https://www.canva.com/photos/MAEJF3SoQQg-installing-new-energy-efficient-windows/

+ Image credit: https://www.canva.com/photos/MAESQnfNUg0-renewable-energy-systems-engineering/