Stopping Distances (AQA GCSE Physics)

Exam Questions

58 mins8 questions
1a2 marks

State two factors that affect the reaction distance.

1b2 marks

State two factors that affect the braking distance.

1c1 mark

A council decides to impose a 20 miles per hour (mph) speed limit in a town centre.

A councillor says that drivers can react more quickly at 20 mph than they can at 30 mph.

Explain what is wrong with the councillor's statement.

1d2 marks

A driver has a reaction time of 0.4 s. 

Their car is travelling at 20 m/s.

Calculate the driver's reaction distance.

   

   

Reaction distance = .................................... m

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2a1 mark

Some sources claim that self-driving cars will be available by the year 2040.

Write down the equation relating reaction time, reaction distance and vehicle speed.

2b2 marks

It takes the average person 1.6 s to hit the brakes if somebody walks into the road in front of the car. 

Calculate the reaction distance in this scenario at a speed of 30 m/s.

2c2 marks

The braking distance for a family car at 30 m/s is 75 m.

Calculate the stopping distance at this speed.   

   

Stopping distance = .................................... m
2d3 marks

A self-driving car has an average "reaction time" of 0.5 s. 

Calculate the stopping distance of a self-driving car with the same brakes as in part (c) travelling at 40 m/s.   

   

Stopping distance = .................................... m

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3a4 marks

Higher Only

Complete the equations. 

Choose quantities from the box. 

Each quantity can be used once, more than once or not at all.

mass force speed
distance energy acceleration

 

     

kinetic space energy space equals space 1 half space cross times space........... space cross times space........... space squared

   

work space done space equals space........... space cross times space...........

3b3 marks

Higher Only

During a braking test, 900 kg car is travelling at 40 m/s.

The test driver must brake sharply and come to a complete stop when he sees a light flash at the end of the road.

Calculate the work done by the brakes to bring the car to a stop.

   

   

Work done = .................................... J
3c2 marks

Higher Only

Safe Motoring Equipment (SME) are a car brake manufacturer.

They state that their brakes can produce a maximum braking force of 6250 N.

Calculate the braking distance of the car from part (b) if the car is using SME brakes.

   

   

Braking distance = .................................... m
3d2 marks

In reality, after the light flashes the car travels further than the value calculated in (c)

Explain why this happens.

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1a2 marks

The graph in Figure 1 shows how the braking distance of a car driven on a dry road changes with the car’s speed.

Figure 1

fig-1-5-8-medium-aqa-gcse-physics

Draw a new line on Figure 1 to show how the braking distance of the car on an icy road changes with speed.

1b2 marks

Student A says that the braking distance can also increase if the driver is intoxicated. Student B says the braking distance can also increase if the driver has worn-out tyres.

Which student is correct? Give a reason for your answer.

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2a2 marks

The graphs in Figure 1 show how the velocity of two cars, A and B, change from the moment the car drivers see an obstacle blocking the road.

Figure 1

fig-1-q2-5-8-medium-aqa-gcse-physics

Using Figure 1, state and explain which car has a smaller stopping distance.

2b2 marks

One of the car drivers was on their phone. The other driver is wide awake and alert.

Determine which driver drove which car.

2c3 marks

A different driver in car C has a stopping distance of 15 m and a thinking distance of 4 m.

Calculate the braking distance of the driver in car C.

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3a3 marks

Table 1 shows the reaction times of three people driving under different conditions.

Table 1

Car driver Reaction time Reaction time in seconds
A Very tired 1.5
B Wide awake with no directions 0.6
C Using a hands-free phone 1.0

Figure 1 show how the thinking distance for the three drivers, A, B and C, depends on how fast they are driving the car.

Figure 1

fig-1-q3-5-8-medium-aqa-gcse-physics

Match each graph line in Figure 1 to the correct driver by writing A, B or C in the box next to the correct line.

3b2 marks

Give two reasons not mentioned in Table 1 as to why driver A would have the longest reaction time.

3c2 marks

Driver B travels at 10 m/s.

Use Figure 1 to determine the thinking distance of driver B. Clearly show your working on the graph.

3d2 marks

Driver B has a braking distance of 6 m.

Calculate the stopping distance for driver B.

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4a3 marks

An investigation was carried out to show how thinking distance, braking distance and stopping distance are affected by the speed of a car.

The results are shown in Table 1 below.

Table 1

Speed in metres per second Thinking distance in metres Braking distance in metres Stopping distance in metres
10   6 12
15 9 14  
20 12 24 36
25 15   53
30 18 55 73

Complete Table 1 by adding in the missing values.

4b2 marks

Figure 1 shows the stopping distance for a family car, in good condition, driven at 20 m/s on a dry road. The stopping distance has two parts.

Figure 1

fig-1-q4b-5-8-medium-aqa-gcse-physics

Complete Figure 1 by adding an appropriate label to the first part of the stopping distance and state one factor that changes both the first part and the second part of the stopping distance.

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5a1 mark

Write down the equation relating braking distance, thinking distance and stopping distance. 

5b3 marks

Midway through a long journey, a lorry driver is travelling along a road at 25 m/s when she spots red traffic lights 200 m ahead.

The lorry driver usually has a reaction time of 0.84 s but she is tired so her reaction time is twice as long. 

Calculate the lorry driver's thinking distance.

   

   

Thinking distance = .................................... m
5c2 marks

Figure 1 is a graph showing braking distances for the average lorry at different speeds in kilometres per hour (km/h).

5-8-m-5c-braking-distance-graph

25 m/s is equal to 90 km/h. The lorry's brakes can produce a deceleration of 3.5 m/s2.

Estimate the stopping distance of the lorry at this speed.

Give your answer to 2 significant figures.   

   

Stopping distance (2 significant figures) = .................................... m
5d1 mark

In reality, the lorry comes to a stop only 5 m before the red light, even with brakes being fully applied. 

Suggest two reasons why this may have happened.

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