1.1.1 SI Base and Derived Units

While the Americans are still clinging on to the imperial system (e.g. 1 foot = 12 inches, 1 pound = 16 ounces), the rest of the world have switched to the metric system (e.g. 1 m = 1000 mm, 1 kg = 1000 g). More precisely, we have adopted the International System of Units (Le Système International d’Unités), aka SI Units, which is built upon 7 base units of 7 base quantities.

What about the units for other quantities? Well, because the other quantities can be defined in terms of these 7 base quantities, their units can always be expressed in terms of base units. They are thus called derived units of derived quantities.

Video Explanation 

Base vs Derived Units

Concept Tests

QQ0001

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