is the product of the mass and velocity of an object, p = m × v

is the principle that states, for a closed system, momentum is always conserved in any interaction

happen when two objects move together and hit each other

happen when a single object splits, or combined objects separate, into pieces that move apart

Conservation of momentum

Combined science

In the Gravity in space unit, they will build on this knowledge to learn about centripetal forces, orbital motion, stellar evolution, red shift and the big bang.

In the Energy of moving objects unit, pupils learnt 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.

This unit explores forces, interactions, and Newton’s laws, including motion, rotation, and momentum. It covers reaction times, stopping distances, and deceleration dangers. Emphasis is on force diagrams, calculations, experiments, and evaluating methods for accuracy and safety.

Forces make things change

the product of the mass and velocity of an object, $$p = m × v$$

for a closed system, momentum is always conserved in any interaction 

happen when a single object splits into pieces that move apart

Match the following key terms to their definition.

a motorcycle of mass 200 kg travelling at 20 m/s

a van of mass 1200 kg travelling at 10 m/s

a car of mass 800 kg travelling at 16 m/s

Starting with the smallest momentum, sort the following objects into order of increasing momentum.

Total momentum increases in explosion interactions.

Total momentum decreases in any collision interactions.

Total momentum is always the same before and after any interaction.

Total momentum decreases in explosion interactions.

Total momentum increases in any collision interactions.

Which of the following is always correct for a closed system of objects that interact with each other?

A toy aeroplane of mass 1.5 kg has a momentum of 30 kg m/s.
Calculate the velocity of the aeroplane.

Two stationary dynamics trolleys are separated by an explosion. Trolley A (mass = 1.5 kg) travels at 3.0 m/s after the explosion. 
Calculate the speed of trolley B (mass = 0.5 kg) after the explosion.

A van (mass = 1600 kg) travelling at 5.0 m/s collides with a stationary car (mass = 900 kg) and they join together.
Calculate the velocity at which they move off after the collision.

Which of the following terms means the highest velocity of an object falling through a fluid?

Which of the following will reduce the total stopping distance of a vehicle?

What size resultant force will cause an object of mass 6.0 kg to accelerate at 20 m/s$$^2$$?

Which of the following relationships can be used to find the acceleration $$a$$ of an object with mass $$m$$ when there is a resultant force $$F$$ acting on it?

A scooter and rider have a combined mass of 150 kg.
Calculate their acceleration when a resultant force of 450 N acts on them. 

A stone of mass 0.5 kg is falling through the air. It has a weight of 5 N and a drag force of 4 N acting upwards on it.
Calculate the acceleration of the stone.
You do not need to include the unit.

This lesson will be removed by end of Summer Term 2025.

Conservation of momentum

Lesson outcome

This lesson will be removed by end of Summer Term 2025.