Basic S.I. Units and its derived unit:

S.I. stands for "System International Units". There are three quantities in the Standard International Systems as concerned to Mechanics which are given below:

Meter: It is distance between the two given parallel lines engraved upon polished surface of a platinum-Iridium bar, kept at 00C at International Bureau of Weights and Measures at Serves, nearby Paris.

Kilogram: It is mass of particular cylinder made of Platinum Iridium kept at International Bureau of Weights and Measures at Serves, nearby Paris.

Second: It is 1/(24 × 60 × 60)^th of the mean solar day. A solar day can be defined as the time interval between instants at which the sun crosses the meridian on two consecutive days.

With the help of the three basic units several units are derived as given below.