Acceleration

Figure 1 shows a person about to dive from a high platform into a pool of water.

The person dived from the platform into the water.

The time taken between the person leaving the platform and entering the water was measured by four people.

The measurements were:

2.1 s 1.9 s 1.3 s 2.0 s

Which measurement is anomalous?

Tick () one box.

Air resistance acted on the person during the dive.

Figure 2 shows the person moving vertically downwards.

Which arrow on Figure 2 shows the direction of the air resistance acting on the person?

Tick () one box.

Air resistance is a contact force.

Which force is also a contact force?

Tick () one box.

What happened to the size of the air resistance force as the speed of the person increased?

After entering the water, the person decelerated for a time of 0.35 s.

The deceleration of the person was 60 m/s².

Calculate the change in velocity of the person.

Use the equation:

change in velocity = deceleration × time

The mass of the person was 75 kg.

Calculate the resultant force on the person when the deceleration was 60 m/s².

Use the equation:

resultant force = mass × deceleration

A student went on a cycling journey that lasted for three days.

The student recorded information about the journey using a cycling app on a mobile phone.

At the start of the journey, the student travelled along a straight road to a road junction.

A map on the cycling app showed the road.

Figure 5 shows the map.

The scale of the map is 1 cm: 20 m

Calculate the distance travelled by the student between the start and the

road junction.

Use Figure 5.

The bicycle had a mass of 15 kg.

gravitational field strength = 9.8 N/kg

Calculate the weight of the bicycle.

Use the equation:

weight = mass × gravitational field strength

Figure 6 shows a velocity–time graph for a downhill part of the journey.

The gradient of the graph represents acceleration.

How does Figure 6 show that the acceleration was constant?

As the student accelerated downhill, the forward force on the student was 250 N.

The work done by the forward force was 4500 J.

Calculate the distance travelled as the student accelerated downhill.

Use the equation:

Most of the roads on the journey were not straight.

Figure 7 shows a map of the route taken for the whole journey.

The line in Figure 7 represents the total distance travelled when the student reached the end of the journey.

How does the total distance travelled compare with the magnitude of the displacement of the student from the start?

Tick () one box.

Why is distance a scalar quantity?

Tick () one box.

Figure 8 shows the distance travelled by the student each day.

Calculate the total distance travelled by the student.

Use Figure 8.

The stopping distance of a car is affected by the condition of the brakes and tyres.

A car is being driven around a corner when the driver sees some roadworks.

The driver applies the brakes when the car is 24 m away from the roadworks.

The velocity of the car changes from 18 m/s to 0 m/s.

Calculate the constant deceleration needed to stop the car in a distance of 24 m.

Use the Physics Equations Sheet.

As a safety measure, the speed limit on the road was reduced.

Explain how the safety of road users is affected by:

• the condition of the brakes and tyres

• reduced speed.

You should refer to thinking distance and braking distance.

Two identical cars were driven along a straight, level road.

One car had a greater speed than the other car.

The driver of each car applied the brakes until the cars stopped.

Both cars travelled the same distance while braking.

Explain how braking from a greater speed affected the risk of the brakes overheating.

The stopping distance of a car is affected by the condition of the brakes and tyres.

A car is being driven around a corner when the driver sees some roadworks.

The driver applies the brakes when the car is 24 m away from the roadworks.

The velocity of the car changes from 18 m/s to 0 m/s.

Calculate the constant deceleration needed to stop the car in a distance of 24 m.

Use the Physics Equations Sheet.

As a safety measure, the speed limit on the road was reduced.

Explain how the safety of road users is affected by:

• the condition of the brakes and tyres

• reduced speed.

You should refer to thinking distance and braking distance.

Two identical cars were driven along a straight, level road.

One car had a greater speed than the other car.

The driver of each car applied the brakes until the cars stopped.

Both cars travelled the same distance while braking.

Explain how braking from a greater speed affected the risk of the brakes overheating.

A triathlon race consists of swimming, cycling and running.

One athlete in a triathlon swims at a speed of 1.5 m/s.

How does the athlete’s swimming speed compare with the typical speed of a person walking?

Tick () one box.

Figure 8 shows a speed–time graph for the athlete for the whole triathlon.

The cycling part of the race was on a straight road.

The work done by the forward force on the bicycle was 110 000 J.

Determine the mean forward force on the bicycle.

Use the Physics Equations Sheet.

Figure 8 is repeated below.

The first part of the run was on a circular track.

The time taken for the athlete to run round the track was 100 s.

Describe the velocity of the athlete during the first 100 s of the run.

Use Figure 8.

After running round the track once, the rest of the run was on a straight, horizontal road.

Explain how Figure 8 shows that the magnitude of the deceleration of the athlete increased.

Figure 1 shows a skydiver jumping from an aeroplane.

The skydiver is accelerating downwards.

Which force causes the skydiver to accelerate?

Tick () one box.

Which force increases as the skydiver accelerates?

Tick () one box.

Figure 2 shows the two forces acting on the skydiver a few seconds after jumping from the aeroplane.

Calculate the resultant force acting on the skydiver in Figure 2.

Eventually the skydiver stops accelerating and falls at a constant velocity.

What is the resultant force acting on the skydiver when falling at a constant velocity?

Tick () one box.

What name is given to the constant velocity of the skydiver?

Tick () one box.

Figure 3 shows a velocity–time graph for the skydiver.

How many seconds did the skydiver accelerate for?

Use Figure 3.

What was the constant velocity of the skydiver?

Use Figure 3.

After opening a parachute, the skydiver fell at a constant speed of 3.6 m/s for 25 seconds.

Calculate the distance travelled by the skydiver during this time.

Use the equation:

distance travelled = speed × time

A safety test was carried out to determine how the speed of a car affects the stopping distance of the car.

At the start of the test the car was moving slowly.

Then the car accelerated at 5.8 m/s² for 2.5 s.

The final velocity of the car was 20 m/s.

Calculate the initial velocity of the car.

Use the Physics Equations Sheet.

The reaction time of the driver was measured.

How can the reaction time of the driver be used to calculate the thinking distance?

The car was driven at a constant speed. The driver applied the maximum braking force, and the braking distance was measured.

The test was repeated at different speeds.

Figure 8 shows the results.

Which of the following gives the relationship between the speed and the braking distance?

Tick () one box.

During one test the brakes were applied with a force of 6250 N.

The deceleration of the car was 5.0 m/s².

The braking distance of the car was 14.4 m.

Determine the momentum of the car before the brakes were applied.

Use the Physics Equations Sheet.

Use Figure 8.

Momentum = kg m/s

Rockets have been developed so that people who are not trained astronauts can pay to travel to space.

Figure 9 shows the passenger module and the propulsion module of a rocket.

The propulsion module burns a large volume of fuel.

The rocket was initially stationary on the ground.

Then the rocket accelerated upwards until it reached a height of 40 km.

The constant acceleration of the rocket was 6.48 m/s².

Calculate the velocity of the rocket at a height of 40 km.

Use the Physics Equations Sheet.

Explain how the weight of the rocket changed as it accelerated upwards.

At a height of 40 km, the rocket stopped burning fuel.

The rocket continued upwards to its maximum height of 60 km.

Explain why the velocity of the rocket decreased between a height of 40 km and a height of 60 km.

At a height of 60 km the two modules of the rocket separated and the passenger module fell back to Earth.

Figure 10 shows the passenger module falling towards the Earth’s surface.

Using parachutes causes the passenger module to fall with a lower terminal velocity than if parachutes were not used.

Explain why the parachutes allow the passenger module to fall with a lower terminal velocity.

A car contains a device called a black box. The black box records the distance travelled and the time taken for each journey. Figure 3 shows the distance–time graph for part of a journey.

Which feature of Figure 3 shows that the car travels at a constant speed for the first 4 seconds? Tick (✓) one box.

After 4 seconds the driver applied the brakes and the car slowed down and stopped. The distance the car travelled after the brakes were applied is called the braking distance. Determine the braking distance of the car. Use Figure 3.

The black box also records the deceleration of the car.

As the car decelerates, the velocity of the car changes by 16 m/s. The car decelerates for 2.5 seconds. Calculate the deceleration of the car. Use the equation:

If the black box records large decelerations, it identifies that the driving may be dangerous. Why can large decelerations be dangerous? Tick (✓) two boxes.

The black box monitors the speed of the car. Describe how speed affects braking distance.

A student investigated how the acceleration of a trolley is affected by the force acting on the trolley. Figure 3 shows some of the equipment used.

Describe a method the student could use. Your answer should include any extra equipment needed.

Table 1 shows one set of results for a similar investigation.

Which of Newton’s laws predicts that the acceleration of the trolley is proportional to the resultant force on the trolley? Tick (✓) one box.

Determine the acceleration of the trolley when the resultant force is 3.6 N. Use Table 1.

Use the Physics Equations Sheet to answer questions 02.4 and 02.5.

Write down the equation that links acceleration (a), mass (m) and resultant force (F).

A resultant force of 0.42 N acts on a different trolley.

Calculate the mass of the trolley.

Figure 9 shows a child dropping a stone into water.

When the child drops the stone it passes the child’s feet with a velocity of 3.1 m/s. The child’s feet are 6.3 m above the water. acceleration due to gravity = 9.8 m/s² Calculate the velocity of the stone as it hits the water. Use the Physics Equations Sheet. Give your answer to 2 significant figures.

Velocity is a vector. Describe the velocity of the stone as it falls through the air. Assume there is no air resistance.

Figure 10 shows the stone just after it has entered the water.

As the stone moves through the water, the stone slows to a constant velocity. Explain why.

Figure 4 shows an apple hanging from a tree. The X marks the centre of mass of the apple.

Draw an arrow on Figure 4 to represent the weight of the apple.

The apple has a mass of 0.150 kg gravitational field strength = 9.8 N/kg Calculate the weight of the apple. Use the equation: weight = mass × gravitational field strength

The apple in Figure 4 is stationary. Why is the apple stationary? Tick (✓) one box.

When the apple is ripe it falls from the tree and accelerates towards the ground.

Why does the apple accelerate? Tick (✓) one box.

The acceleration of the apple is 9.8 m/s² The velocity of the apple changes from 0 to 4.9 m/s Calculate the time taken for the apple to fall to the ground. Use the equation:

The stopping distance of a car is the sum of the thinking distance and the braking distance.

Which factors affect the thinking distance? Tick (✓) two boxes.

Explain why a person should not drink alcohol and then drive.

The Highway Code gives information on how thinking distance depends on the speed

of a car. Figure 7 shows the information as a graph.

What is the speed of a car if the thinking distance is 16 m?

Describe the relationship between speed and thinking distance.

The Highway Code assumes the driver’s reaction time is 0.70 seconds. Draw a line on Figure 7 to show the relationship for a driver with a reaction time of 1.4 seconds.

A car accelerates at 5.0 m/s² over a distance of 45 m initial velocity of the car = 0 m/s Calculate the final velocity of the car. Use the Physics Equations Sheet. Give your answer to 2 significant figures.

Figure 10 shows competitors in the wheelchair race at the London Marathon. The distance of the London Marathon is 42 000 m

Use the Physics Equations Sheet to answer questions 07.1 and 07.2.

Write down the equation that links distance (s), force (F) and work done (W).

During the race competitors work against air resistance. The work done against air resistance by the winner of the race was 3 360 000 J Calculate the average air resistance acting on the winner of the race.

Use the Physics Equations Sheet to answer questions 07.3 and 07.4.

Which equation links distance travelled, speed and time? Tick (✓) one box.

The distance of the London Marathon is 42 000 m The winning time for the race was 5600 seconds. Calculate the average speed of the winner of the race.

Explain why the speed of a competitor changes during the race.

The distance a car travels during the driver’s reaction time is called the thinking distance.

Figure 9 shows how thinking distance depends on speed for a car.

Determine the driver’s reaction time. Use the Physics Equations Sheet.

Figure 10 shows how the velocity of a car changes during braking.

Determine the braking distance of the car.

Explain how the gradient of the line on Figure 10 shows that the resultant force on the car was not constant.

Figure 11 shows a stationary apple hanging from a tree. The X marks the centre of mass of the apple.

Draw two arrows on Figure 11 to show the forces acting on the apple.

It takes 0.50 s for the apple to fall to the ground. The initial velocity of the apple is 0 m/s acceleration due to gravity = 9.8 m/s² Calculate the distance fallen by the apple. Use the Physics Equations Sheet.

In Question 07.2 it was assumed that the acceleration was a constant 9.8 m/s² Evaluate this assumption.

The stopping distance of a car is the sum of the thinking distance and the braking distance.

The thinking distance is affected by the reaction time of the driver.

Which two of the following can affect the reaction time of the driver?

Tick (✓) two boxes.

Scientists measured the reaction time for drivers of different ages.

Figure 6 shows the results.

At what age did the drivers have the lowest mean reaction time?

What was the lowest mean reaction time?

The braking distance of a car is the distance travelled between the driver applying the

brakes and the car stopping.

Complete the sentences.

Choose answers from the box.

Each answer may be used once, more than once or not at all.

When the brakes are applied, the kinetic energy of the

car.

The temperature of the brakes.

A car is travelling at a speed of 12 m/s.

The driver applies the brakes and the car decelerates at a constant 3.0 m/s².

Calculate the braking distance of the car.

Use the equation:

Choose the unit from the box.

To pass the UK driving test, people must know the typical stopping distance of a car at certain speeds.

Suggest one reason why.

Professional rugby players wear a tracking device that measures their velocity and acceleration.

Figure 9 shows a player wearing a tracking device.

The player is tackling another player who is running with the ball.

Velocity and acceleration are both vector quantities.

What is a vector quantity?

Tick (✓) one box.

Which of the following is a vector quantity?

Tick (✓) one box.

Figure 10 shows a velocity–time graph for the player running with the ball.

Determine the acceleration of the player between 0 and 1.6 s.

Describe the motion of the player between 3.4 s and 3.6 s.

The force exerted on the player when she is tackled causes her to accelerate.

Write down the equation which links acceleration (a), mass (m) and resultant force (F).

The player accelerates at 25 m/s² when a resultant force of 1800 N acts on her.

Calculate the mass of the player.

The tracking device sends data to a computer during the game.

Suggest one advantage of the data being sent during the game.

Professional rugby players wear a tracking device that measures their velocity and acceleration. Figure 2 shows a player wearing a tracking device. The player is tackling another player who is running with the ball.

Velocity and acceleration are both vector quantities. What is a vector quantity? Tick (✓) one box.

Which of the following is a vector quantity? Tick (✓) one box.

Figure 3 shows a velocity–time graph for the player running with the ball.

Determine the acceleration of the player between 0 and 1.6 s.

Describe the motion of the player between 3.4 s and 3.6 s.

The force exerted on the player when she is tackled causes her to accelerate.

Write down the equation which links acceleration (a), mass (m) and resultant force (F).

The player accelerates at 25 m/s² when a resultant force of 1800 N acts on her. Calculate the mass of the player.

The tracking device sends data to a computer during the game. Suggest one advantage of the data being sent during the game.

Figure 1 shows a girl bowling a ball along a ten-pin bowling lane.

The girl is trying to knock down the ten pins at the end of the bowling lane. As the ball travels along the lane the velocity of the ball decreases.

Velocity is a vector. Which statement describes a vector? Tick (✓) one box.

Why does the velocity of the ball decrease as the ball travels along the lane? Tick (✓) one box.

The ball travels along the lane at an average speed of 4.5 m/s It takes the ball 4.0 seconds to travel the length of the lane. Calculate the length of the lane. Use the equation: distance travelled = speed × time

Figure 2 shows the ball hitting one of the pins.

Draw an arrow on Figure 2 to show the force of the pin on the ball.

The velocity of the pin changes from 0 to 12 m/s It takes 0.15 seconds for the velocity to change. Calculate the acceleration of the pin. Use the equation:

When the pin is struck it accelerates. Complete the sentences. Choose answers from the box. Each answer can be used once, more than once, or not at all.

The displacement of the pin from the girl. The mass of the pin. The kinetic energy of the pin.

A student investigated how the height of a ramp affects the acceleration of a trolley down the ramp. Figure 11 shows some of the equipment used.

Plan an investigation to determine how the height of the ramp affects the acceleration of the trolley.

Table 2 shows the results.

The first two results have been plotted on Figure 12.

Complete Figure 12. You should:

• label the axes

• plot the remaining results from Table 2

• draw a line of best fit.

Write down the equation that links acceleration (a), mass (m) and resultant force (F).

When the resultant force on the trolley was 0.63 N the acceleration of the trolley

Calculate the mass of the trolley.

A student investigated how the height of a ramp affects the acceleration of a trolley down the ramp. Figure 3 shows some of the equipment used.

Plan an investigation to determine how the height of the ramp affects the acceleration of the trolley.

Table 1 shows the results.

The first two results have been plotted on Figure 4.

Complete Figure 4. You should:

• label the axes

• plot the remaining results from Table 1

• draw a line of best fit.

Write down the equation that links acceleration (a), mass (m) and resultant force (F).

When the resultant force on the trolley was 0.63 N the acceleration of the trolley

Calculate the mass of the trolley.

Figure 9 shows a runner using a smart watch and a mobile phone to monitor her run.

Figure 10 is a velocity–time graph for part of the runner’s warm-up.

Determine the total time for which the velocity of the runner was increasing.

Determine the deceleration of the runner.

The smart watch and mobile phone are connected to each other by a system called Bluetooth.

Bluetooth is wireless and uses electromagnetic waves for communication.

Suggest why the phone and watch being connected by a wireless system is an advantage when running.

Write down the equation that links frequency, wave speed and wavelength.

The electromagnetic waves have a frequency of 2 400 000 000 Hz

The speed of electromagnetic waves is 300 000 000 m/s

Calculate the wavelength of the electromagnetic waves.

Table 3 shows some information about four types of Bluetooth.

Mobile phones use type 2 Bluetooth to communicate with other devices.

Suggest two reasons why.

Figure 1 shows a runner using a smart watch and a mobile phone to monitor her run.

Figure 2 is a velocity–time graph for part of the runner’s warm-up.

Determine the total time for which the velocity of the runner was increasing.

Determine the deceleration of the runner.

The smart watch and mobile phone are connected to each other by a system called Bluetooth.

Bluetooth is wireless and uses electromagnetic waves for communication.

Suggest why the phone and watch being connected by a wireless system is an advantage when running.

Write down the equation that links frequency, wave speed and wavelength.

The electromagnetic waves have a frequency of 2 400 000 000 Hz

The speed of electromagnetic waves is 300 000 000 m/s

Calculate the wavelength of the electromagnetic waves.

Table 1 shows some information about four types of Bluetooth.

Mobile phones use type 2 Bluetooth to communicate with other devices.

Suggest two reasons why.

Figure 9 shows a free body diagram for an aeroplane flying at a constant speed and at a constant height.

The speed of the aeroplane is much greater than the speed at which the aeroplane lands.

Explain how the forces need to change so the aeroplane can land.

The aeroplane lands at a speed of 80 m/s

After landing, the aeroplane takes 28 s to decelerate to a speed of 10 m/s

The mean resultant force on the aeroplane as it decelerates is 750 000 N

Calculate the mass of the aeroplane.

Which of these is a scalar quantity?

Tick one box.

A woman cycled along a straight flat road.

Figure 1 shows how the woman’s velocity changed with time.

Which part of the graph shows the woman moving at constant velocity?

Tick one box.

Which part of the graph shows the woman stationary?

Tick one box.

Between points A and B the woman was accelerating.

Use Figure 1 to determine the total time for which she was accelerating.

Use Figure 1 to determine her increase in velocity between points A and B.

Calculate her acceleration between points A and B.

Use the equation:

Estimate how a typical cycling speed of 6 m/s compares with a typical walking speed.

Tick one box.

Figure 8 shows the distance-time graph for a car travelling at 15 m/s

When the driver is tired, his reaction time increases from 0.50 seconds to 0.82 seconds. Determine the extra distance the car would travel before the driver starts braking.

When the brakes are used, the temperature of the brakes increases. Explain why. Use ideas about energy in your explanation.

A lorry travels 84 m with a constant acceleration of 2.0 m/s² to reach a velocity of 19 m/s Calculate the initial velocity of the lorry. Use the Physics Equations Sheet.

Figure 9 shows how the thinking distance, braking distance and stopping distance for a car vary with the speed of the car.

Describe the relationships shown in Figure 9 You should include factors that would affect the gradient of the lines.