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

Deceleration is used to describe a change in velocity where the object slows down.

The velocity of an object is the speed in a particular direction. This is the rate of change of displacement.

The change in velocity is represented by 𝚫v.

A rate of change is how much a quantity is changing by every second.

Calculating acceleration (a = Δv/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

how fast something is moving in a particular direction

a change in velocity where the object is slowing down

a symbol used to represent change in velocity

Match the key words and phrases to their explanations.

Match the quantities to the unit definitions.

acceleration = change in velocity ÷ time

acceleration = change in velocity × time

Which of these equations correctly give acceleration ($$a$$)?

A car takes 17.6 s to accelerate from 0 m/s to 44 m/s.
Calculate the acceleration of the car in m/s$$^2$$.
You do not need to enter the unit.

A motorcycle reduces its velocity from 25 m/s to 14 m/s in 5.5 s.
Calculate the deceleration.

A cricket ball moving at 20 m/s is hit by a bat, and then travels in the opposite direction at 15 m/s. The impact lasts for 0.05 s.
Calculate the acceleration.
You do not need to enter the unit.

Which international standard unit is used to measure speed and velocity in physics?
Give the symbol.

A lorry is travelling along a straight road. Its speed increases from 5.6 m/s to 8.4 m/s.
What is the change in velocity for the lorry? 

A roller-skater covers a distance of 520 m in 40 s.
Calculate their speed.

How far will a wind-up toy travel if it has a speed of 0.2 m/s and it moves for 1 minute? 
Give the correct unit.

How long will it take a rocket traveling at 5.0 km/s to travel a distance of 500 m?

This lesson will soon be taken down.

Calculating acceleration (a = Δv/t)

Lesson outcome