Quantities and Units
Quantities, Symbols and Units
Physics often involves looking at quantities:

A symbol is used to represent a quantity (v for speed)

A unit is what the quantity is actually measured in (m/s for speed)
Base Units and Derived Units
There are seven base units used in physics from which all the others can be derived:

Base units are the metre, kilogram, second, ampere, kelvin, mole and candela

Derived units include metres per second and kilograms per cubic metre
Unit Prefixes
It is often more convenient to add a prefix to very small or very large quantities.
Converting Units: Example A
A worked example where units are converted from one form to another.
Converting Units: Example B
Here we convert units for area and volume.
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