Difference between scalar and vector qunatities

Class 9 Physics - Easy Notes Scalar and Vector Quantities




Scalar and Vector Quantities
Class 9 Physics - Easy Notes | English Medium | Federal Board Friendly


Learning Goals
After reading these notes, you should be able to define scalar and vector quantities,
differentiate between them, identify examples, and solve simple short questions.



1. Physical Quantity
A physical quantity is any measurable property of a body or a phenomenon. It is expressed by
a numerical value and a unit.

• Example: length = 5 m, mass = 2 kg, time = 10 s.

Easy Point
A physical quantity tells us how much of something is measured and in which unit it is
measured.


2. Scalar Quantities
A scalar quantity is a physical quantity that has magnitude only. It does not have direction.

Here, magnitude means the numerical value with its unit.

• Example: mass = 5 kg. It only tells the amount of matter, not any direction.

Common examples of scalar quantities:
Mass Time Speed Distance

Temperature Energy Work Power

Volume Density Charge Pressure


3. Vector Quantities
A vector quantity is a physical quantity that has both magnitude and direction.

• Example: displacement = 10 m east. It tells the amount of change in position and the
direction.



Vector quantity shows magnitude + direction

Magnitude: 10 m
East
Example: displacement = 10 m towards East




Common examples of vector quantities:



Prepared for quick revision - English Medium Page 1