The system of units which is accepted internationally for measurement is called international system of unit.

The SI, with standard scheme of symbols, units and abbreviations was developed and recommended by General conference on weights and measures in 1971 for international uses in scientific, technical, industrial and commercial work.

Some other common system of units used in mechanics are-

(I) FPS (Foot, Pound, Second) System

(II) CGS (Centimetre, Gram, Second) System

(III) MKS (Metre, Kilogram, Second) System

(IV) Some Other etc.

In SI system, there are 7 base units and 2 supplementary units.