Scalars and Vectors

This lesson explains the difference between scalar and vector quantities, including how to add vectors and find the resultant force, as required by the Edexcel GCSE Combined Science specification (1SC0). Understanding scalars and vectors is fundamental to describing motion and forces correctly.

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Scalar Quantities

A scalar quantity has magnitude (size) only. It does not have a direction.

Scalar Quantity	SI Unit
Distance	m
Speed	m/s
Mass	kg
Time	s
Energy	J
Temperature	K or °C
Power	W

Examples

• A car has a speed of 30 m/s. This tells you how fast it is going, but not which way.
• A bag of sugar has a mass of 1 kg. Mass does not depend on direction.

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Vector Quantities

A vector quantity has both magnitude and direction.

Vector Quantity	SI Unit
Displacement	m
Velocity	m/s
Acceleration	m/s²
Force	N
Momentum	kg m/s
Weight	N