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AQA GCSE Physics Your notes
Forces & their Interactions
Contents
Scalars & Vectors
Contact & Non-Contact Forces
Forces as Vectors
Weight, Mass & Gravity
Calculating Weight
Resultant Forces
Free Body Diagrams
Balanced & Unbalanced Forces
Page 1 of 43
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Scalars & Vectors
Your notes
Scalars & Vectors
All quantities can be one of two types:
A scalar
A vector
Scalars
Scalars are quantities that have only a magnitude
For example, mass is a scalar quantity since it is a quantity that has no direction to it
Vectors
Vectors have both a magnitude and a direction
Velocity is a vector quantity since it is described with both a magnitude and a direction
When describing the velocity of a car it is necessary to mention both its speed and the direction in
which it is travelling
For example, 60 km per hour in a Westerly direction
Distance is a value describing only how long an object is or how far it is between two points - this
means it is a scalar quantity
Displacement on the other hand also describes the direction in which the distance is measured - this
means it is a vector quantity
For example, 100 km in a Northern direction
Comparing Scalars & Vectors
The table below lists some common examples of scalar and vector quantities:
Scalars & Vectors Table
Page 2 of 43
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Your notes
Some vectors and scalars are similar to each other
For example, the scalar quantity distance corresponds to the vector quantity displacement
Corresponding vectors and their scalar counterparts are aligned in the table where applicable
Examiner Tips and Tricks
Make sure you are comfortable with the differences between similar scalars and vectors, the most
commonly confused pairings tend to be:
Distance and displacement
Speed and velocity
Weight and mass
Students often find the difference between distance and displacement confusing. Distance
measures the length of the path you take to get from point A to point B. This includes all the twists
and turns you take. Displacement measures the length of a line between Point and A and Point B if
Page 3 of 43
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, Head to www.savemyexams.com for more awesome resources
you used a ruler to join points A and B on a map. You would also draw the arrowhead on that line to
show that you travelled from point A to point B.
Your notes
The reason this is important is because displacement is often less than the distance travelled, so this
has consequences in calculations.
Representing Vectors
A vector can be represented by using an arrow
The length of the arrow represents the magnitude of the vector
The direction of the arrow indicates the direction of the vector
Two forces represented by arrows.
Force A has a larger magnitude than Force B. Force A is directed to the right and slightly upwards,
whereas Force B is directed to the left and slightly upwards.
Worked Example
A tennis ball is thrown at an angle of 45° to horizontal at a speed of 5 m/s. A second tennis ball is
thrown in the same direction at a speed of 10 m/s. Draw the velocity vectors of the balls.
Answer:
Step 1: Draw the first tennis ball and its velocity vector
Measure the 45° angle with a protractor
Page 4 of 43
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AQA GCSE Physics Your notes
Forces & their Interactions
Contents
Scalars & Vectors
Contact & Non-Contact Forces
Forces as Vectors
Weight, Mass & Gravity
Calculating Weight
Resultant Forces
Free Body Diagrams
Balanced & Unbalanced Forces
Page 1 of 43
© 2015-2025 Save My Exams, Ltd. · Revision Notes, Topic Questions, Past Papers
, Head to www.savemyexams.com for more awesome resources
Scalars & Vectors
Your notes
Scalars & Vectors
All quantities can be one of two types:
A scalar
A vector
Scalars
Scalars are quantities that have only a magnitude
For example, mass is a scalar quantity since it is a quantity that has no direction to it
Vectors
Vectors have both a magnitude and a direction
Velocity is a vector quantity since it is described with both a magnitude and a direction
When describing the velocity of a car it is necessary to mention both its speed and the direction in
which it is travelling
For example, 60 km per hour in a Westerly direction
Distance is a value describing only how long an object is or how far it is between two points - this
means it is a scalar quantity
Displacement on the other hand also describes the direction in which the distance is measured - this
means it is a vector quantity
For example, 100 km in a Northern direction
Comparing Scalars & Vectors
The table below lists some common examples of scalar and vector quantities:
Scalars & Vectors Table
Page 2 of 43
© 2015-2025 Save My Exams, Ltd. · Revision Notes, Topic Questions, Past Papers
, Head to www.savemyexams.com for more awesome resources
Your notes
Some vectors and scalars are similar to each other
For example, the scalar quantity distance corresponds to the vector quantity displacement
Corresponding vectors and their scalar counterparts are aligned in the table where applicable
Examiner Tips and Tricks
Make sure you are comfortable with the differences between similar scalars and vectors, the most
commonly confused pairings tend to be:
Distance and displacement
Speed and velocity
Weight and mass
Students often find the difference between distance and displacement confusing. Distance
measures the length of the path you take to get from point A to point B. This includes all the twists
and turns you take. Displacement measures the length of a line between Point and A and Point B if
Page 3 of 43
© 2015-2025 Save My Exams, Ltd. · Revision Notes, Topic Questions, Past Papers
, Head to www.savemyexams.com for more awesome resources
you used a ruler to join points A and B on a map. You would also draw the arrowhead on that line to
show that you travelled from point A to point B.
Your notes
The reason this is important is because displacement is often less than the distance travelled, so this
has consequences in calculations.
Representing Vectors
A vector can be represented by using an arrow
The length of the arrow represents the magnitude of the vector
The direction of the arrow indicates the direction of the vector
Two forces represented by arrows.
Force A has a larger magnitude than Force B. Force A is directed to the right and slightly upwards,
whereas Force B is directed to the left and slightly upwards.
Worked Example
A tennis ball is thrown at an angle of 45° to horizontal at a speed of 5 m/s. A second tennis ball is
thrown in the same direction at a speed of 10 m/s. Draw the velocity vectors of the balls.
Answer:
Step 1: Draw the first tennis ball and its velocity vector
Measure the 45° angle with a protractor
Page 4 of 43
© 2015-2025 Save My Exams, Ltd. · Revision Notes, Topic Questions, Past Papers
