year 8 maths

328 Chapter 5 Ratios and rates
Fun run investigation
Investigation
Three maths teachers, Mrs M, Mr P and Mr A, trained very hard to compete in a Brisbane Fun Run. The
10.44 km route passed through the botanical gardens, along the Brisbane River to New Farm Park, and
back again.
Their times and average stride lengths were:
• Mrs M: 41 minutes, 50 seconds: 8 strides per 9 m
• Mr P: 45 minutes, 21 seconds: 7 strides per 9 m
• Mr A: 47 minutes, 6 seconds: 7.5 strides per 9 m
Copy and complete the following table and determine which rates are the most useful representations of
fitness. Give the answers rounded to one decimal place. Justify your conclusions.
Running rates Mrs M Mr P Mr A World record 10 km runners Your family member or friend
Seconds per 100 m
Seconds per km
Metres per minute
Km per hour
Strides per 100 m
Strides per minute
Strides per hour
Fitness investigation
1 Using a stopwatch, measure your resting heart rate in beats per minute.
2 Run on the spot for one minute and then measure your working heart rate in beats per minute.
3 Using a stopwatch, time yourself for a 100 m run and also count your strides. At the end, measure your
heart rate in beats per minute. Also calculate the following rates.
• your running rate in m/s, m/min and km/h
• your running rate in time per 100 m and time per km
• your rate of strides per minute, strides per km and seconds per stride
4 Run 100 m four times without stopping and, using a stopwatch, record your cumulative time after each
100 m .
• Organise these results into a table.
• Draw a graph of the distance you ran (vertical) vs time taken (horizontal).
• Calculate your running rate in m/min for each 100 m section.
• Calculate your overall running rate in m/min for the 400 m .
• Explain how and why your running rates changed over the 400 m .
5 Try sprinting really fast over a measured distance and record the time. Calculate your sprinting rate in
each of the following units.
• minutes per 100 m • time per km
• metres per minute • km per hour
6 Research the running rate of the fastest schoolboy and schoolgirl in Australia. How do their sprinting
rates compare with the running rates of Australian Olympian athletes?
Cambridge Maths NSW
Stage 4 Year 8 Second edition
ISBN 978-1-108-46627-1 © Palmer et al. 2018
Cambridge University Press
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