Motion Graphs (Cambridge (CIE) AS Physics)

Revision Note

Ashika

Written by: Ashika

Reviewed by: Caroline Carroll

Updated on

Motion graphs

  • There are five types of graph that can represent motion 

Distance-time graphs

  • On a distance-time graph…

    • slope equals speed

    • the y-intercept equals the initial position

    • a straight (diagonal) line represents a constant speed

    • a curved line represents an acceleration

    • a positive slope represents motion in the positive direction

    • a negative slope represents motion in the negative direction

    • a zero slope (horizontal line) represents a state of rest

    • the area under the curve is meaningless

Displacement-time graphs

  • On a displacement-time graph…

    • slope equals velocity

    • the y-intercept equals the initial position

    • a straight (diagonal) line represents a constant velocity

    • a curved line represents an acceleration

    • a positive slope represents motion in the positive direction

    • a negative slope represents motion in the negative direction

    • a zero slope (horizontal line) represents a state of rest

    • the area under the curve is meaningless

Displacement-time graphs for different scenarios

Motion graphs (1), downloadable AS & A Level Physics revision notes

The displacement-time graph for constant velocity is a straight diagonal line, and for acceleration is a curve

Speed-time graphs

  • On a speed-time graph…

    • slope equals acceleration

    • the y-intercept equals the initial speed

    • a straight line represents uniform acceleration

    • a curved line represents non-uniform acceleration

    • a positive slope represents an increase in speed 

    • a negative slope represents a decrease in speed 

    • a zero slope (horizontal line) represents motion with constant speed

    • the area under the curve equals the distance travelled

Velocity-time graphs

  • On a velocity-time graph…

    • slope equals acceleration

    • the y-intercept equals the initial velocity

    • a straight line represents uniform acceleration

    • a curved line represents non-uniform acceleration

    • a positive slope represents an increase in velocity in the positive direction

    • a negative slope represents an increase in velocity in the negative direction

    • a zero slope (horizontal line) represents motion with constant velocity

    • the area under the curve equals the displacement 

Velocity-time graphs for different scenarios

Motion graphs (2), downloadable AS & A Level Physics revision notes

The velocity-time graph for constant velocity is a straight horizontal line, for acceleration is a straight diagonal line and for increasing acceleration is a curve

Acceleration-time graphs

  • On an acceleration-time graph…

    • slope is meaningless

    • the y-intercept equals the initial acceleration

    • a zero slope (horizontal line) represents an object undergoing constant acceleration

    • the area under the curve equals the change in velocity

Acceleration-time graph for different scenarios

Motion graphs (3), downloadable AS & A Level Physics revision notes

The acceleration-time graph for constant velocity is blank, for increasing velocity is a straight horizontal line and for increasing acceleration is a straight diagonal line

Examiner Tips and Tricks

Always check the axes when dealing with graphs. The differences between distance-time graphs and displacement-time graphs, and speed-time graphs and velocity-time graphs are subtle but important. Make sure you know what you are looking at before answering any graph questions in the exam.

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Ashika

Author: Ashika

Expertise: Physics Project Lead

Ashika graduated with a first-class Physics degree from Manchester University and, having worked as a software engineer, focused on Physics education, creating engaging content to help students across all levels. Now an experienced GCSE and A Level Physics and Maths tutor, Ashika helps to grow and improve our Physics resources.

Caroline Carroll

Author: Caroline Carroll

Expertise: Physics Subject Lead

Caroline graduated from the University of Nottingham with a degree in Chemistry and Molecular Physics. She spent several years working as an Industrial Chemist in the automotive industry before retraining to teach. Caroline has over 12 years of experience teaching GCSE and A-level chemistry and physics. She is passionate about creating high-quality resources to help students achieve their full potential.