# Edexcel Additional Science P2a Topic 09 Lesson 08 - Collins

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```					                                                Take a brake
Unit P2a
Topic 9
Lesson 8

Specification reference                                             Other lessons in this book
P2.9.15    Present an argument to explain how the stopping          P2: 9.1 How fast?
distance of a vehicle depends on the speed of            P2: 9.4 Forcing the pace
travel.
P2.9.16    Discuss the impact of factors such as driver’s
reaction time and the condition of the vehicle and

Student Book pages 210 to 211
Worksheet P2: 9.8(1)
Worksheet P2: 9.8(2)
Worksheet P2: 9.8(3)
Worksheet P2: 9.8(4)
Technician’s notes P2: 9.8

braking distance                reaction time                    stopping distance                   thinking distance

 Review distance  speed  time (low/standard demand)
 Ask pupils to write down how the distance travelled at a certain speed is changed by:
a doubling the time of travel, b halving the time of travel, c travelling for 10 times as long.
 Ask pupils to write down how the distance travelled in a certain time is changed by:
a doubling the speed, b halving the speed, c travelling at ten times the speed.
 Ask pupils to write down how the distance travelled is changed by:
doubling the speed and doubling the time of travel.
 Review acceleration  force/mass (standard/high demand)
 Ask pupils to write down how the acceleration of an object with a certain mass is changed by:
a doubling the force acting, b halving the force acting.
 Ask pupils to write down how the acceleration caused by a certain force is changed by:
a doubling the mass of the object being acted on, b halving the mass of the object being acted on.

Learning outcomes
 explain what is meant by ‘thinking distance’ and ‘braking distance’
 state that stopping distance  thinking distance  braking distance
Teaching and learning activities                                                 Resources

Pupils make a reaction timer using the worksheet to guide them.                                  Technician’s notes P2: 9.8
Ask the pupils to answer questions 1 to 4 from the Student Book.
 Worksheet P2: 9.8(1)
 Student Book page 210
Learning outcomes
   explain what is meant by ‘thinking distance’ and ‘braking distance’
   state that stopping distance  thinking distance  braking distance
   describe factors that will affect thinking distance
   describe factors that will affect braking distance
Teaching and learning activities                                           Resources

Pupils investigate the effect of speed on braking distance. The worksheet will guide them.      Technician’s notes P2: 9.8
This can be a demonstration or done by groups of pupils if sufficient equipment and space
is available.
 Worksheet P2: 9.8(2)
Ask the pupils to answer questions 5 to 8 from the Student Book.
 Student Book page 211

Learning outcomes
   explain what is meant by ‘thinking distance’ and ‘braking distance’
   state that stopping distance  thinking distance  braking distance
   describe factors that will affect thinking distance
   describe factors that will affect braking distance
   calculate thinking, braking and stopping distances
Teaching and learning activities                                           Resources

Pupils investigate other factors affecting braking distance. The worksheets will guide them.      Technician’s notes P2: 9.8
These can be done as demonstrations or by groups of pupils if sufficient equipment is
   Worksheet P2: 9.8(3)
available.
   Worksheet P2: 9.8(4)
Ask pupils to answer questions 9 to 12 from the Student Book.
Go through the answers.                                                                           Student Book page 211

 Pupils choose one or more of ‘thinking distance’, ‘braking distance’ or ‘stopping distance’ as answers to these statements:
–   always greater than the braking distance
–   proportional to speed
–   increased by drinking alcohol
–   increased by luggage in the car
–   increased by ice on the road.
 Ask pupils to write down three things they could do to minimise each of:
– thinking distance
– braking distance.

LOW DEMAND                             STANDARD DEMAND                                 HIGH DEMAND
1 Thinking distance increases as            6 30 m/s  0.5 s  15 m                    12 Stopping distance  8 m  30 m
speed increases                           7 10 000 N/1000 kg  10 m/s
2                                  38 m
2 Braking distance increases as speed                            2
8 a 15 m/s/10 m/s  1.5 s
increases.                                                     2
b 30 m/s/10 m/s  3 s