© Nuffield Foundation 2011 Nuffield Free-Standing Mathematics Activity Road test © Brett Wilson

© Nuffield Foundation 2011© Nuffield Foundation 2011

Nuffield Free-Standing Mathematics Activity

Road test

© Brett Wilson


In this activity you will use data from a speed test to draw and interpret graphs.

© Brett Wilson


Drivers have always been interested in how fast cars go – and how quickly they stop!

Graphs provide a useful illustration of the data.


Think about…What comments can you make?Why do you think the true and indicated speeds are different?

Here are some data from a speed test.Acceleration from rest

Time True Speed Indicated Speed

t (seconds) v (miles per hour) u (miles per hour)

2.3 30 34

3.5 40 45

5.5 50 55

6.8 60 66

9.4 70 78

13.1 80 89

20.5 90 99


The brakes were also tested by measuring the distance travelled by the car in coming to rest from different speeds. The track surface was dry and maximum braking was used.

Why are only dry surfaces used for the tests?

How might the results be different if wet road tests were included?

Brakes

True speed Distance

v (miles per hour) d (metres)

30 9.5

50 27.5

70 52.4

85 98.7


Sports car accelerating

0

20

40

60

80

100

0 20 40 60 80 100

Indi

cate

d sp

eed

(mph

)

True speed (mph)

Graph of indicated speed against true speed

Series1



0

20

40

60

80

100

0 5 10 15 20 25

True

spee

d (m

ph)

Time (s)

Graph of true speed against time

True Speed (miles per hour)



0

20

40

60

80

100

0 5 10 15 20 25

Indi

cate

d sp

eed

(mph

)

Time (s)

Graph of indicated speed against time


Sports car braking

0

20

40

60

80

100

0 20 40 60 80 100

Dis

tanc

e (m

etre

s)

Speed (mph)

Graph of distance against speed


Reflect on your work

What does each graph tell you about the car’s performance during the test drive?

Road test

Documents

© Nuffield Foundation 2011 Nuffield Free-Standing Mathematics Activity Road test © Brett Wilson