Give me a brake
20m
15m
10m
5m
0m
|
Select a speed |
|
Select a vehicle |
|
Select tyres |
|
Select a road surface |
|
Select the weather |
|
Start the test, then brake |
|
Record your results |
km/h
Braking...
Test
failed
failed
| Braking distance (m) | |
| Distance to target (m) |
Set the starting
speed of the
vehicle.
speed of the
vehicle.
Choose a vehicle to
test from the list
below.
test from the list
below.
Select tyres for the
vehicle from the list
below.
vehicle from the list
below.
Select a road
surface from the
list below.
surface from the
list below.
Select a type of
weather from the
list below.
weather from the
list below.
Select the Start test
button (or press the
SPACE BAR) to move.
Brake to stop as close
to the finish line as
possible without running over it.
button (or press the
SPACE BAR) to move.
Brake to stop as close
to the finish line as
possible without running over it.
Record your results
from the read-outs
below.
from the read-outs
below.
Your task
What you need to do
In this activity, you're going to predict how different vehicles and road conditions affect braking distance. Here's what to do:
Choose your speed.
Select a vehicle.
Choose the tyres for the vehicle.
Choose a road type.
Choose the weather conditions.
Select Start test to move the vehicle. To try to stop as close to the finish as you can, select Brake. Then record the results for your investigation.
Select a vehicle.
Choose the tyres for the vehicle.
Choose a road type.
Choose the weather conditions.
Select Start test to move the vehicle. To try to stop as close to the finish as you can, select Brake. Then record the results for your investigation.
Enter the braking distance and conditions into a table. You can
a sample table for recording data. Print it and enter your results.
Answer these questions.
a sample table for recording data. Print it and enter your results.
Answer these questions.
Which type of vehicle has the shortest braking distance?
Which conditions result in the shortest braking distance?
Which conditions result in the longest braking distance?
Which conditions result in the shortest braking distance?
Which conditions result in the longest braking distance?
Test your knowledge with the Challenges.
Your task
Example results table
Give me a brake
Results from laboratory
Results from laboratory
| Speed | Vehicle | Tyres | Road | Weather |
Braking distance (m) |
Distance from target (m) |
Information
Some helpful facts
Tyres have different types of surfaces that affect the friction between them and a road.
The greater the number of tyres in contact with a road surface, the greater the friction forces between the vehicle and the road.
Weather conditions affect the amount of friction between a tyre and the road.
While the speed of the vehicle does not affect friction, speed is important in determining stopping distance.
The mass of a vehicle also affects the stopping distance. Usually, the greater the mass, the greater the stopping distance.
Normally when a car brakes, it does not skid to a stop. In fact, antilock braking systems (ABS) on many cars prevent wheels from skidding on any road surface when the brakes are applied.
Glossary
1 / 3
Defining the words
Antilock Braking System (ABS): An antilock braking system is a mechanism
in some cars that prevents tyres from locking up and skidding. Whenever a
tyre starts to lock, a feedback system reduces the braking forces on that tyre,
preventing it from skidding. This allows a more effective and controlled
braking.
Bald tyre: A bald tyre is one where the tread has worn
away to an almost smooth surface. This is a very
dangerous state.
dangerous state.
Bald tyre
Braking distance: Braking distance is the distance covered by a car from the
time the brakes are applied until the vehicle comes to a complete stop.
Friction: Friction is a force that opposes sliding when two surfaces
rub together.
Reaction time: In this exercise, reaction time is the time taken between any
indication that the brakes must be applied, and when they are actually
applied. Reaction times are made longer by many factors, including lack of
attention, tiredness and drugs of any sort.
Glossary
2 / 3
Defining the words
Reaction time distance: Reaction time distance is the distance covered (metres)
by a car during a reaction time. It is obtained by multiplying the
speed of the vehicle (metres/second) by the reaction time (seconds). If you
prefer to work in kilometres per hour for speed, the distance covered during
a reaction time is obtained by multiplying the speed (km/h) by reaction time
(seconds), and dividing the result by 3.6.
Skid: Skids occur when the tyres on a car lock up after application of the brakes.
When a tyre skids on the road, friction between the tyre and road is
the main force that stops the car. Heat and sound energy are two products of
a skid. The stopping distance in a skid is greater than under controlled
braking when the tyres do not lock up.
Glossary
3 / 3
Defining the words
Slick tyre: A slick tyre is a type of tyre used in motor racing
that has no tread pattern. While it is very good in dry
weather, the lack of a tread is a problem in wet conditions.
weather, the lack of a tread is a problem in wet conditions.
Total stopping distance: Total stopping distance is the distance obtained by
adding the reaction time distance to the braking distance.
Treaded tyre: A treaded tyre is the standard tyre on a car. A
tread, the patterned surface of a tyre, helps to reduce
risks of a skid when driving on wet roads.
risks of a skid when driving on wet roads.
Slick tyre
Treaded tyre
Challenges
Test and extend your knowledge
These challenges will test your knowledge of car skids and braking. You may have to research the answers for some of them.
Does a car stop more quickly when it skids to a stop, or when an antilock
braking system does not allow a skid? Explain your answer.
How do antilock brake systems work in cars?
Speed limits on suburban roads in many parts of Australia have been
reduced from 60km/h to 50km/h. How much does this reduce the average
stopping distance of cars?
Help
Keyboard shortcuts and sound controls
The up and down arrow keys on the keyboard change the speed of the vehicle.
Press the SPACE BAR to get the vehicle started, and then to brake.
Press the SPACE BAR to get the vehicle started, and then to brake.
You can select and activate buttons using the keyboard.
Press the TAB key to select a button. Then press the ENTER key to activate it. To move backwards through the buttons, press the SHIFT and TAB keys together.
Press the TAB key to select a button. Then press the ENTER key to activate it. To move backwards through the buttons, press the SHIFT and TAB keys together.
Select the speed of the
animation.
animation.
Use this button to turn off or turn back on all sounds.
Use these buttons to adjust the sound volume.
