Chapter 1 Measurements - Physical Quantities

Physical Quantities

Those quantities which can be measured accurately are called physical quantities. The foundation of physics rests upon physical quantities.

For Example: mass, length, time, velocity, force, density, temperature, electric current, etc.

Types: Physical quantities are of two types

Base Quantities: These are the minimum number of those physical quantities in terms of which other physical quantities can be defined.

For Example: length, mass, time, etc.

Derived Quantities: The quantities whose definitions are based on other physical quantities are called derived quantities.

For Example: velocity, acceleration, force, etc.

The measurement of a base quantity involves following two steps:

1. The choice of a standard
2. Estblishment of a procedure for comparing the quantity to be measured with two characteristics:
1. It is accessible
2. It is invariable