Any physical quantity can be characterized by dimensions. The magnitudes assigned to the dimensions are called units.
The system of units used in Engineering is the Systeme International d’Unites also known as International System of Units and is based on the metric system.
A unit has to have a special name and symbol. The usefulness of a unit is as a means of communicating to everyone who does science how it was particularly defined.
Are classified into two types:
- Basic Units
- Derived Units
BASIC UNITS: Basic units are those units from which other units are derived. Some basic dimensions such as mass m, length L, time t, and temperature T are referred to as Basic dimensions.. Basic units are also known as primary or fundalmental units.
NOTE: Length, Mass, Time are basic quantities, while their units(meter, kilogram, seconds) are basic units.