System of units

The following are popular systems of units in use.

1 .CGS System : In this system, Centimeters, Gram, and Second are the fundamental units of length, mass and time respectively. This system if units is still popular in many areas of science, technology, engineering and commerce.
2. FPS System : In this system, Foot, Pound and Second are the fundamental units of length, mass and time respectively. This system is in use in only a few countries specially in commerce. In science, technology and industry it has become almost redundant.
3. MKS System : In this system, Meter, Kilogram, and Second are the fundamental units of length, mass and time respectively. This system is most widely used in science, engineering and commerce. When supplemented by four other base units, they make SI system of units.
4. SI Units : This system of units is abbreviated from System International d' units ( International System of Units ). It is an internationally accepted system and is widely used in science and engineering. It consist of the three fundamental units-meter, kilogram and second - supplemented by units of temperature ( Kelvin, K ), electric current ( ampere, A ), luminous intensity (candela, cd) and amount of a substance ( mole). Units of the above seven quantities are referred to as base units. In addition to these seven units, units of angle ( radian, rad ) and solid angle (sterdian, Sr ) are also used in SI system as supplementary units.

Units of some physical quantities in different system are listed in table 1.1. The seven base and two supplementary units in SI are listed in table 1.2 and 1.3. Table 1.4 is devoted to list several derived SI unit.

TABLE1.1:SOME PHYSICAL QUANTITIES AND THEIR UNITS

UNITS PHYSICAL QUANTITIES SYSTEM CGS MKS/SI FPS FUNDAMENTAL LENGTH CM  M  FT MASS GM KG LB TIME SEC S S DERIVED  VELOCITY CM/S M/S FT/S ACCELERATION CM/S^2  M/S FT/S FORCE DYNE NEWTON, N POUNDAL ENERGY ERG JOULE, J FT,POUNDAL POWER ERG/S WATT,W FT.POUNDAL/S TABLE1.2:BASE SI UNIT

UNITS	PHYSICAL QUANTITIES	SYSTEM
		CGS	MKS/SI	FPS
FUNDAMENTAL	LENGTH	CM	M	FT
	MASS	GM	KG	LB
	TIME	SEC	S	S
DERIVED	VELOCITY	CM/S	M/S	FT/S
	ACCELERATION	CM/S^2	M/S	FT/S
	FORCE	DYNE	NEWTON, N	POUNDAL
	ENERGY	ERG	JOULE, J	FT,POUNDAL
	POWER	ERG/S	WATT,W	FT.POUNDAL/S

	TABLE1.3:SUPPLEMENTARY SI UNITS S.NO PHYSICAL QUANTITY UNIT SYMBOL 1 ANGEL RADIAN RAD 2 SOLID ANGEL STERADIAN SR