Measurements and the systems of units

System of units: 

     A set of fundamental and derived units is called a system of units. 

Names of system of units: 

• M.K.S System 
• C.G.S System 
• British Engineering System 
• System International (S.I ) 

(i) M.K.S System (Meter, Kilogram, Second System): 

In this system fundamental units of length, mass and time are meter, kilogram and second respectively. 
Units of other physical quantities can be expressed in terms of meter , kilogram and second. 

(ii) C.G.S System (Centimeter, Gram, Second System): 

In this system the fundamental units of length, mass and time are centimeter, gram and second respectively. 

(iii) British Engineering System:

In this system length, force and time are taken as fundamental quantities. Hence the fundamental units are taken as foot for length, pound for force and second for time. 

• This system is also known as F.P.S system. 
• Mass is taken as a derived quantity, it's unit is Slug.

(iv) System International (S.I ) units:

This system of units was introduced in 1960 and is now in use all over the world. This system of units is based on the following seven independent fundamental units.