The initial velocity of an object is the velocity it starts with during a phase of motion.

The final velocity of an object is the velocity it finishes with after a phase of motion.

The average velocity of an object travelling in a straight line is the change in distance divided by the time taken.

The average acceleration of an object is the change in velocity divided by the time taken.

When the acceleration is constant, it is described as uniform acceleration.

Motion calculations (a=(v–u)/t, v²−u²=2ax & 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

the velocity of an object at the start of a time period

the velocity of an object at the end of a time period

the rate of change of displacement over a time period

the rate of change of velocity over a time period

Match the key words or phrases to their definitions.

Which of these shows the correct relationship between initial velocity $$u$$, final velocity $$v$$, acceleration $$a$$ and distance $$x$$? 

A race car increases its velocity from 12 m/s to 48 m/s in a time of 6.0 s.
Calculate the acceleration of race car.

A motorcycle slows with a deceleration of –5.0 m/s² from 25 m/s to a stop.
Calculate the distance the motorcycle takes to come to a stop.

An aeroplane starting from rest needs to reach a take–off velocity of 60 m/s to take off from a runway of length 1500 m.
Calculate the minimum acceleration the airplane will need.

A rocket is stationary on the moon. It launches vertically with a constant acceleration of 5.0 m/s².
Calculate its vertical speed when it has reached a height of 1.96 km.

Match the quantity to the correct example measurement of it.

The gradient of a displacement–time graph gives the acceleration.

The gradient of a displacement–time graph gives the velocity.

The gradient of a velocity–time graph gives the acceleration.

The gradient of a velocity–time graph gives the distance travelled.

The gradient of a velocity–time graph gives the speed.

Which of the following statements about motion graphs are correct?

A jogger travels at an average speed of 4.0 m/s.
Calculate the time it will take them to travel 1 km.

A jet travels a distance of 9000 m in 1 minute.
Calculate the speed of the jet in m/s.

A firework rocket is launched from rest and reaches a speed of 20 m/s in 0.25 s.
Calculate the acceleration of the rocket.

An oil tanker increases its velocity from 0.5 m/s to 6.5 m/s in a time of 120 s.
Calculate the acceleration of the oil tanker.

Starter Quiz