Power

Work

Fundamental Units of F.P.S, C.G.S, M.K.S and S.I

Workshop Calculation & Science - Fitter

Unit, Fractions - Classification of Unit

Necessity

All physical quantities are to be measured in terms of standard quantities.

Unit

A unit is defined as a standard or fixed quantity of one kind used to measure other quantities of the same kind.

Classification

Fundamental units and derived units are the two classifications.

Fundamental Units

Units of basic quantities of length, mass and time.

Necessity
All physical quantities are to be measured in terms of standard quantities.

Unit
A unit is defined as a standard or fixed quantity of one kind
used to measure other quantities of the same kind.

Classification
Fundamental units and derived units are the two classifications.

Fundamental units
Units of basic quantities of length, mass and time.

• F.P.S system is the British system in which the basic units of length, mass and time are foot, pound and second respectively.
• C.G.S system is the metric system in which the basic units of length, mass and time are centimeter, gram and seconds respectively.
• M.K.S system is another metric system in which the basic units of length, mass and time are metre, kilogram and second respectively
• S.I. units are referred to as Systems International units which is again of metric and the basic units, their names and symbols are as follows.

Prime Numbers and Whole Numbers

Factor

A factor is a number which divides another number exactly.

Examples:

To find the factors of 24, 72, 100:

• 24 = 2 × 2 × 2 × 3
• 72 = 2 × 2 × 2 × 3 × 3
• 100 = 2 × 2 × 5 × 5

The numbers 2, 3, 5 are called factors.

Prime Factor

A prime factor is a prime number which divides a given number exactly.

Example:

57 = 3 × 19

The numbers 3 and 19 are prime factors.

Electrical Quantities

Force

In C.G.S System:
Force (Dyne) = Mass (g) × Acceleration (cm/s²)

In F.P.S System:
Force (Poundal) = Mass (lb) × Acceleration (ft/s²)

In M.K.S System:
Force (Newton) = Mass (kg) × Acceleration (m/s²)

Lowest Common Multiple (L.C.M)

Definition

The Lowest Common Multiple (LCM) of a group of numbers is the smallest number that is exactly divisible by all the given numbers.

Prime Factorization Method

Example 1: Find LCM of 20, 66, 128

• 20 = 2 × 2 × 5
• 66 = 2 × 3 × 11
• 128 = 2 × 2 × 2 × 2 × 2 × 2 × 2

Take highest powers of all prime factors:

LCM = 2⁷ × 3 × 5 × 11 = 42240

Example 2: Find HCF of 78, 128, 196