Momentum (AQA GCSE Physics)

Higher Tier Only

At a paintballing party, a group of children fire paint balls at each other using paintball guns.

The paintball guns have a mass of 0.5 kg each.

Each paintball inside the gun has a mass of 2.5 g.

Describe and explain the momentum of the paintball before the gun is fired.

Use the information above to support your answer.

Higher Tier Only

The gun fires the paintball forwards at a velocity of 70 m / s.

The paintball has a mass of 2.5 g

Calculate the momentum of the paintball just after the gun is fired.

Higher Tier Only

Compare the total momentum of the gun and paintball before and after the gun is fired, assuming no other forces were acting on the objects.

Use information from (a) and (b) above in your answer.

Momentum is a vector quantity.

Explain why.

In Figure 1, a boulderer is at rest while climbing. His foot then slips and he lands on a crash pad containing foam.

Figure 1

He takes 1.01 s to fall.

Calculate the boulderer's speed before hitting the crash pad.

Acceleration due to gravity = 9.81 m/s².

Give your answer to 3 significant figures.

   Speed (3 significant figures) = .................................... m/s

Higher Tier Only

The boulderer has a mass of 75.5 kg.

From the moment he makes contact with the crash pad, he comes to rest in 0.00925 s.

Calculate the force the crash pad exerts on the boulderer.

Give your answer to 3 significant figures.

   Force (3 significant figures) = .................................... N

While landing, the boulderer bends his knees.

Explain how this reduces the chance of injury.

Higher Tier Only

Car A has a mass of 600 kg and is travelling at at 30 miles per hour (miles/hour) to the right.

Car B is behind car A and is travelling at 40 miles/hour to the right.

The total momentum of the system is 58 000 kg miles/hour.

Calculate the mass of car B.

Give your answer to 2 significant figures.

   Mass of car B (2 significant figures) = ........................... kg

Higher Tier Only

The driver of car B is on their phone and they crash into the back of car A.

After the collision, both cars stick together and travel forward at the same speed. 

Calculate the combined speed of the cars, giving the unit. 

Give your answer to 2 significant figures.

   Combined speed (2 significant figures) = .............. Units ..........

Higher Tier Only

Show that kinetic energy is not conserved in this collision.

Higher Tier Only

Modern cars all feature crumple zones, which are designed to buckle and break in the event of a crash, as shown in Figure 1.

Derive the equation from the equations  and , where  is force,  is change in momentum,  is time,  is acceleration,  is change in velocity and  is mass.

Explain how the crumple zone of the car reduces the risk of injury in a crash.

Using the equation relating force and momentum given in part (a), explain why driving at a lower velocity is generally safer. 

Explain whether it is safer for the passenger to crash into a wall or a parked vehicle.

Higher Tier Only

A young girl jumps off the edge of a shopping trolley.

The trolley is stationary at the moment the girl jumps.

The girl jumps backwards.

Describe and explain, using the idea of momentum, what happens when the girl jumps off the trolley.

Higher Tier Only

The mass of the trolley is 7.5 kg and the mass of the girl is 36 kg.

Calculate the velocity at which the girl moves forwards if the trolley moves backwards with a velocity 1.2 m / s

Higher Tier Only

A car driver brakes to stop his vehicle when he sees the vehicle in front is not moving to avoid a collision.

The driver did not stop his vehicle in time.

It collides with the stationary vehicle in front, joining the two together. 

Figure 1 shows both vehicles, before and just after the collision.

Figure 1

The momentum of the two vehicles colliding was conserved.

Describe what is meant by that statement.

Higher Tier Only

Calculate the velocity of the two joined vehicles immediately after the collision.

Show clearly how you work out your answer.

Give your answer to 2 significant figures.

Higher Tier Only

It is a requisite of the law that all cars manufactured in the UK must have seat belts.

The driver of vehicle 1 in Figure 1 was not wearing his seatbelt when the collision occurred.

Explain why he was injured and how the seatbelt could have reduced the risk of injury.

Higher Tier Only

The conservation of momentum applies when two moving objects collide, and no other forces act upon them

Explain what is meant by ‘conservation of momentum’.

Higher Tier Only

The conservation of momentum applies when two vehicles are involved in a collision.

Give two other types of event in which conservation of momentum applies.

Higher Tier Only

A physics teacher sets up a demonstration to teach her Year 10 class ideas about the conservation of momentum.

Figure 2 shows a straight, horizontal air track and two air track trolleys, S and T, which can move along it.

Figure 2

T has a mass of 3 10^-1 kg and its velocity is 1.4 m / s to the left. S has a mass of 200 g and is stationary.

When T collides with S they stick together.

Calculate the velocity of the trolleys after the collision.

Show your working clearly and give the unit and direction.

Higher Tier Only

Describe the assumptions you made when calculating the velocities of the trolleys after the collision. 

Higher Tier Only

A bullet, fired from a gun, has a momentum of 4 kg m/s before it hits a target.

It takes 0.0025 s for the bullet to be stopped by the target.

Calculate the force needed to stop the bullet.

Show clearly how you work out your answer, giving any equations that you use.