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Year 11
OCR
Higher

Stopping (and estimating stopping distances)

I can describe the factors that affect stopping distance and explain the effect of each one.

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New
New
Year 11
OCR
Higher

Stopping (and estimating stopping distances)

I can describe the factors that affect stopping distance and explain the effect of each one.

Download all resources
Share activities with pupils

Lesson details

Key learning points

  1. Stopping distance is the distance travelled both as a drive reacts and then for the brakes to bring a vehicle to a stop
  2. Reaction time of a drive can be affected by tiredness, drugs, alcohol or distractions
  3. Braking distance can be affected by adverse road and weather conditions and the condition of the vehicle
  4. When braking, work is done on the brakes that heats them up
  5. If brakes overheat they can stop working effectively and lead to a loss of control

Common misconception

Pupils often forget to include thinking distance in the overall stopping distance, or imagine that thinking distance is too short to matter.

Model a situation in which a child steps out from behind a parked car 10 m in front of a driver. At 20 mph the thinking distance is about 6 m and braking distance 6 m; at 30 mph these are 9 m and 14 m.

Keywords

  • Reaction time - for driving is the time between noticing a hazard and taking an action to deal with it

  • Thinking distance - is the distance a vehicle travels while a driver reacts; the vehicle does not slow during this time

  • Braking distance - is the distance a vehicle travels between the brakes being applied and the vehicle coming to a stop

  • Stopping distance - is the sum of the thinking and braking distances

Let pupils estimate stopping distances in different scenarios based on the charts in the lesson and information about the vehicle, e.g. a lorry will have longer stopping distances because it has greater mass.
Teacher tip

Content guidance

  • Risk assessment required - equipment

Supervision

Adult supervision required

Licence

This content is © Oak National Academy Limited (2024), licensed on Open Government Licence version 3.0 except where otherwise stated. See Oak's terms & conditions (Collection 2).

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Starter quiz

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6 Questions

Q1.
Which force is caused by two solid surfaces moving across each other?
drag
electromagnetic
Correct answer: friction
gravitational
upthrust
Q2.
When a vehicle increases its speed, it is accelerating and when it decreases its speed, it is ...
Correct Answer: decelerating, decelerate, decelerates
Q3.
The figure shows a dynamics trolley just after it has reached the end of a ramp. Which of the following statements help explain why the trolley slows down when it has left the ramp?
An image in a quiz
The size of the forward force is increasing.
Correct answer: There is no forward force acting on the trolley.
A drag force pushes the trolley forwards.
Correct answer: A frictional force acts in the direction opposite to the movement.
Correct answer: A drag force acts in the direction opposite to the movement.
Q4.
Which of the following is the correct equation for calculating the kinetic energy of an object?
kinetic energy = mass × speed
kinetic energy = ½ × mass × speed
kinetic energy = ½ × (mass)$$^2$$ × speed
Correct answer: kinetic energy = ½ × mass × (speed)$$^2$$
kinetic energy = ½ × (mass)$$^2$$ × (speed)$$^2$$
Q5.
A motorcycle is travelling at 9.00 m/s. How far will the motorcycle travel in 1.40 s?
0.15 m
6.43 m
7.60 m
10.4 m
Correct answer: 12.6 m
Q6.
A motorcycle has a mass of 200 kg and is travelling at 9.00 m/s. Calculate the kinetic energy of the motorcycle. Give the unit.
Correct Answer: 8100 J, 8100J, 8.1 kJ, 8.1kJ

Exit quiz

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6 Questions

Q1.
Match the following key terms to their definitions.
Correct Answer:reaction time,time between noticing a hazard and taking an action to deal with it

time between noticing a hazard and taking an action to deal with it

Correct Answer:thinking distance,distance a vehicle travels during the time a driver takes to react

distance a vehicle travels during the time a driver takes to react

Correct Answer:braking distance,distance a vehicle travels before stopping after brakes are pressed

distance a vehicle travels before stopping after brakes are pressed

Correct Answer:stopping distance,sum of the thinking and braking distances

sum of the thinking and braking distances

Q2.
Where is most of the energy from the kinetic store transferred to when a vehicle brakes and slows down?
to the chemical store, increasing the amount of fuel
Correct answer: to the thermal store, heating the brakes
to the thermal store, heating the engine
to the gravitational store, raising the vehicle up a hill
Q3.
Which of the following factors affect both the thinking distance and the braking distance of a vehicle?
wet roads
worn tyres
alcohol consumption
Correct answer: vehicle speed
caffeine consumption
Q4.
A driver with a reaction time of 1.2 s is travelling at 30 m/s along a road. Calculate the thinking distance for this driver. Give the correct unit.
Correct Answer: 36 m, 36 metres, 36m
Q5.
The driver of a lorry travelling at 12.0 m/s notices a hazard. The driver's reaction time is 0.80 s and, at this speed, the braking distance of the lorry is 25.0 m. Calculate the stopping distance.
13.0 m
29.6 m
Correct answer: 34.6 m
Q6.
A car is travelling at 30 m/s and, at this speed, its braking distance is 75 m. Calculate the minimum reaction time needed to stop the car in less than 90 m. Give the correct unit.
Correct Answer: 0.5 s, 0.50s, 0.5 seconds, 0.50 seconds