Fundamental and derived quantities

Introduction to quantities

In Physics, we measure things like how long a road is, how heavy a bag of garri feels, or how long a generator runs. These are called physical quantities. A physical quantity is anything you can measure with an instrument and give a number to.

Basic quantities in life

Think about building a house. You need to know the length of the land, the mass of the cement, and the time the workers spend. These three are the foundation of everything else. In Physics, we call these basic building blocks fundamental quantities.

What are fundamental quantities

Fundamental quantities are the basic physical quantities that do not depend on any other quantities for their measurements.

Basically, they are the 'parents' that do not come from anywhere else.

The seven pillars of Physics

There are seven fundamental quantities recognized by scientists worldwide. However, for your WAEC or JAMB, the three most common ones you must master are Length (measured in metres), Mass (measured in kilograms), and Time (measured in seconds). The others are Temperature (Kelvin), Electric Current (Ampere), Luminous Intensity (Candela), and Amount of Substance (Mole).

What are derived quantities

When you combine two or more fundamental quantities by multiplying or dividing them, you get something new. For example, if you multiply the length of a room by its width, you get Area. These are called derived quantities.

Simply put, these are the 'children' born from combining fundamental quantities.

Common examples of derived quantities

Some common derived quantities include:

Area: This is Length times Width (Length x Length).

Volume: This is Length times Width times Height (Length x Length x Length).

Speed: This is Distance (Length) divided by Time.

Force: This is Mass multiplied by Acceleration.

Worked example on derived units