What I the difference between fundamental and derived quantities?

- Fundamental quantities are quantity whose definition does not depend on other quantities.

There are seven fundamental quantities in physics:

Length (measured in metres)

Mass (in kilograms)

Time (in seconds)

Electric current (in Ampere)

Temperature (in Kelvin)

Amount of substance (in moles)

Luminous intensity (in candela)

- On the other hand, derived quantities are quantities that are defined using the fundamental quantities.

For example, derived quantities are:

Velocity, which is the ratio between length and time

Acceleration, which is the ratio between velocity and time

Energy, which is a product of mass and velocity squared

And many others.