Braking Distance and Speed
Group Practical Investigation.
• The PE staff have loaned us the bikes. Treat
them in a way that shows we respect the
property and know how to treat other
people’s property.
Aim: to find out the relationship
between speed and braking
distance.
• Independent Variable: Speed of the bike
• Dependent Variable: Braking distance
• Controlled – mass of bike and rider, quality
of bike, distance over which speed is
measured, stopwatch operator, ground
conditions.
Method:
1. Make sure the rider can ride the bike in a
straight line and operate the brakes.
2. Set up a 20 m distance over which the bike
will travel at a constant speed.
3. Ride the bike towards the constant speed
zone.
4. Start the stop watch as the bike enters the
zone, stop as it reaches the 20m line.
5. Brake uniformly at the 20m line and
measure to the point where the bike stopped.
6. Repeat 6 times at different speeds.
Results.
Trial Distance Time
1
20 m
2
20 m
3
20 m
4
20 m
5
20 m
6
20 m
Braking
distance
An Excel
Spreadsheet is
prepared to carry
out the
calculations for
speed and to plot
the graph of your
results – But you
will need to print
the graph.
Conclusion
• What is the relationship between speed and
braking distance?
• Is it linear (as speed doubles braking
distance doubled)?
• Does it appear more complex than that?