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Units and dimensions- Mechanical education


Units and Dimensions are used to represent the standard form of measurements for an object or a body. They are used for enhance the characteristics such as Area, Volume, Force, Density, Energy etc.of different objects in different fields.


A dimension is a word which is used to describes the measurable characteristics of a particular object or a body such as
Weight, height, length and temperature etc.
A unit is standard form  for measuring the dimensions which has some universal indications to identify the dimensions.
Units and Dimensions are used for enhance the characteristics of different objects.
Some of the examples are given below for clear explanation.
The dimensions used are expressed in some fundamental dimensions such as.
Mass (M) – Kg
Area(A)- M2
Velocity(V)- m/sec
Length (L) – m
Volume(v)- M3
Time (T) – S
Temperature (t) –
0C or K (Kelvin)


1. Density: 

Mass per unit volume=kg/m3

2. Newton: 

Unit of force expressed in terms of mass and acceleration.
. F=Mass x Acceleration = kg – m/sec2= Newton.

3. Pascal: 

A Pascal is the pressure produced by a force of Newton uniformly applied
over an area of 1 m2.               Pressure = Force per unit area = N/ m2= Pascal or Pa.

4. Joule: 

A joule is the work done by applying 1 Newton force.                              Work = Force per unit area = N
m = J or Joule.

5. Watt: 

A Watt is used to represents the work done which is equivalent to the Joule done per second.
Power = Work done per unit time = J/ Sec = W or Watt.
There are some measurement units given below for clear explanation:
Area:         Square meters.
Volume:    Cubic meters.
Velocity:    Meters per second.
Torque:      Newton meters.
Energy:      Joule
Work:        Joule
Angular velocity:   Radians per second
Density:      Kg per cubic meter.
Pressure:    Newtons per square meter.
Acceleration:   Meters per square second.

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