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© Nuffield Foundation 2011 Free-Standing Mathematics Activity Speed and distance
8

Speed and distance

Feb 09, 2016

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Free-Standing Mathematics Activity. Speed and distance. How can we model the speed of a car? How will the model show the distance the car travels?. v mph. 70. 0. 2. t hours. Using a graph. Think about How far will it travel in 2 hours?. Car travelling at 70 mph. Area = 2 × 70 = 140. - PowerPoint PPT Presentation
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Page 1: Speed and distance

© Nuffield Foundation 2011

Free-Standing Mathematics Activity

Speed and distance

Page 2: Speed and distance

© Nuffield Foundation 2011

• How can we model the speed of a car?• How will the model show the distance the car travels?

Page 3: Speed and distance

© Nuffield Foundation 2011

Using a graph

Car travelling at 70 mph

Area = 2 × 70 = 140

This is the distance travelled, 140 miles

v mph

t hours0 2

70

Think aboutHow far will it travel in 2 hours?

Page 4: Speed and distance

© Nuffield Foundation 2011

Car accelerating steadily from 0 to 72 kph in 10 seconds

Distance travelled = 100 metres

= 100

v kph

t seconds0 10

72

72 kph =

7210006060

10202

= 20 metres per second

20 ms-1

Area of triangle

baseheight2

Think aboutWhat was the car’s average speed? What is the connection with the graph?

Page 5: Speed and distance

© Nuffield Foundation 2011

Car accelerating steadily from 18 ms-1 to 30 ms-1 in 5 seconds

Distance travelled = 120 metres

= 24 × 5

Area of a trapezium

Area =

(1830)52

v ms-1

t seconds0

18

30

5

= 120

(a b) h2

a

b

h

Think aboutWhat was the car’s average speed? What is the connection with the graph?

Page 6: Speed and distance

© Nuffield Foundation 2011

Car travelling between 2 sets of traffic lights

Area of A

252

t (s)v (ms-1)

00

25

48

88

105

120

69

0

v ms-1

t seconds1262 4 8 10

A AC C BB

= 70

Area of C

89 22

= 17

Area of B

58 22

= 13

Total area

= 5

Distance travelled = 70 metres

8

5

9

Think about Why are the strips labelled A, B & C? How will this help to find the area?

Think aboutIs this a good estimate? How can it be improved?Is the graph realistic?

Page 7: Speed and distance

© Nuffield Foundation 2011

Area =

Car travelling with speed v = 0.5t3 – 3t2 + 16

t (s)v (ms-1)

0 1 2 43

16 13.5 8 02.5

v

t0

16

421 3

13.5

82.5

1613.5 12

12.52

13.58 1

2

82.5 1

2

= 14.75 + 10.75+ 5.25 + 1.25

Distance travelled = 32 metres

Think aboutWhat did this car do?

Think aboutHow could this estimate be improved?

Page 8: Speed and distance

© Nuffield Foundation 2011

At the end of the activity

• Explain why using triangles and trapezia can only give an estimate of the area under a curve

• When is an estimate smaller than the actual value? When is it larger?

• How can you improve the estimate?• How well do you think the graphs and functions you

have studied model the actual speed of real cars?• In what way would graphs showing actual speeds

differ from those used in this activity?