Difference between fundamental quantity and derived quantity

Last updated on April 20th, 2023 at 12:10 pm

In this post, we will study the Difference between fundamental quantity and derived quantity. We will also analyze a few physical quantities to find out whether those are fundamental or derived quantities.

Difference between fundamental quantity and derived quantity – with examples

Length, Mass, and Time – Each of these 3 physical quantities doesn’t depend on any other quantity for its measurement. So these 3 are called Fundamental quantities.
Other quantities like velocity, acceleration, and force all depend on more than one fundamental quantity for their measurements. These are called Derived Quantities. [ like velocity depends on length and time measurement ]

How is velocity a derived quantity?

Velocity = displacement /elapsed time. Hence velocity is actually a ratio of some length and some time. That means velocity consists of more than one fundamental quantity. That’s why velocity is a derived quantity.

How is acceleration a derived quantity?

Acceleration is the ratio of change of velocity and elapsed time. Velocity itself is a derived quantity consisting of 2 fundamental quantities, length and time. Hence, acceleration is also a derived quantity.

How is force a derived quantity?

Force is the product of mass and acceleration. Acceleration is itself a derived quantity. Hence force is also a derived quantity.

How is momentum a derived quantity?

Momentum is the product of mass and velocity. Velocity is itself a derived quantity. Hence momentum is also a derived quantity.