A displacement–time graph shows the displacement of an object over a period of time.

A velocity–time graph shows the velocity of an object over a period of time.

The velocity of an object is the rate of change of displacement. This is how fast it is moving in a particular direction.

The acceleration of an object is the rate of change of velocity. This is how much the velocity changes per second.

Calculating from motion graphs (a=(v–u)/t  and v=x/t)

Combined science

In the Energy of moving objects unit, they will build on this knowledge to learn how to calculate the amount of energy of objects have because they are moving, stretched or in a gravitational field; and to calculate energy transfers using knowledge of energy conservation and dissipation.

In the Moving by force unit, pupils learnt how to calculate speed and describe motion using distance-time graphs, apply Newton’s First Law of motion and calculate the amount of energy needed to move an object to a new position.

Measuring and calculating motion

this shows the displacement of an object over a period of time

this shows the velocity of an object over a period of time

Match the key words and phrases to their explanations.

The graph shows the movement of a van over time.
Find the total distance travelled for the journey.

The graph shows the movement of a van making two deliveries.
Find the average speed of the van during the outwards journey, from 0 to 3 hours.

The graph shows the displacement of a dynamics trolley along a bench.
Calculate the velocity of the trolley at time = 2 s. 

Find the distance travelled by this object during the first 4 seconds of motion.

Use the graph to find the acceleration of the moving object between time = 2 s and time = 4 s.

Match the quantity to the unit it is measured in.

What is the velocity of this object at time = 3 s? 

Which of these is a correct definition of acceleration?

During which time period is this object decelerating?

A speedboat increases its velocity from 2.0 m/s to 14 m/s in a time of 8.0 s.
Calculate the acceleration of the speedboat.

The displacement-time graph shows the movement of a robot.
Calculate the velocity of the robot at time = 45 s.

This lesson will soon be taken down.

Calculating from motion graphs (a=(v–u)/t and v=x/t)

Lesson outcome