Unit of Work is Joule(J). Work is one of the most fundamental concepts in physics. It is defined as force that is required to displace an object from its position. The other units of work are erg, kilojoules, foot-pound, kilowatt-hour, etc.
In this article, we will discuss the definition of work in terms of physics, unit of work, SI unit of work, and Conversion between different units of work.
Definition of Work
In Physics, Work is defined as the transfer of energy that occurs when a force is applied to an object, causing it to move a certain distance in the direction of the force.
Work is said to be done when a force acts upon a body and it produces a displacement along the direction of the applied force. It is represented as W. The definition of work in physics describes its relationship to energy – whenever work is done, energy is transferred.
In other words, for work to be done, a force must be exerted, and there must be a displacement in the direction of the force.
What is Unit of Work?
The unit of work is same as the unit of energy because energy can be defined via work. The unit of work is Joule. In physics, work is defined as the product of the force applied to an object and the displacement of the object in the direction of the force.
The other units of work are horsepower-hour, newton-metre, foot-pound, kilowatt-hour, erg, etc.
Formula of Work
Mathematically, work can be represented as:
W = Fd cosθ
Where,
- W = Work done by the force
- F = the force acting on it
- d = Displacement of the force
- θ = the angle between the force vector and the displacement vector
Unit of work depends upon the unit of force i.e. newton (N) and the unit of distance i.e. meter (m), therefore unit of work is N-m which is defined as one joule.
What is 1 Joule?
One joule is defined as the work done when a force of one newton acts over a distance of one meter in the direction of the force.
Dimension Formula of Work
The dimensional formula of work is [M1L2T-2]
Where,
- M = Mass
- L = Length
- T = Time
SI Unit of Work
The SI unit of work is the joule (J). It can be defined as the work done by a force of 1 Newton in moving an object through a distance of 1 meter in the direction of the force.
CGS Unit of Work
In the CGS (centimeter-gram-second) system, the unit of work is the erg. One erg is defined as the work done when a force of one dyne acts over a distance of one centimeter in the direction of the force.
System of Unit | Unit | Equivalent |
|---|---|---|
SI unit | N.m | Joule |
CGS unit | dyne-cm | Erg |
In the SI system, the standard unit of work is the Joule (J). The conversion factor between these units is 1 Joule = 10⁷ ergs.
Unit of Work in other Systems
The unit of work in other systems are as follows:
System | Unit |
|---|---|
International System of Units(SI) | Joule |
CGS | Erg (dyne-cm) |
FPS | Foot-pound |
MKS | Joule |
Othe units of work are as follows:
- horsepower-hour
- newton-metre
- foot-pound
- kilowatt-hour
- litre-atmosphere
Conversion between Units of Work
The conversion between different units of work is described in the table below:
Units | Equivalent units in Joule |
|---|---|
1 erg | 10-7 J |
1 newton-metre | 1 J |
1 foot-pound | 1.35582 J |
1 kilowatt-hour | 3.6 × 106 J |
1 BTU | 1055.06 J |
1 KiloJoule | 1000 J |
1 watt-hour | 3600 J |
Also Check,
Solved Examples on Unit of Work
Example 1: How much work is done to displaced a body 15 m when a force of 140 N is applied on the body?
Solution:
Given,
Displacement (d)= 15 m
Applied force (F)= 140 N
We know,
Work done = F × d = 15 × 140 J
Work done = 2100 J
Therefore, the required work done is 2100 J.
Example 2: If a 10 N force acts on a body and it produces 20 m displacement of the body, then find out the work done?
Solution:
Given,
Displacement (d)= 20 m
Applied force (F)= 10 N
We know,
Work done = F × d = 20 × 10 J
Work done = 200 J
Therefore, the required work done is 200 J.