Dot Point physics preliminary

Brian Shadwick

© Science Press 2007 First published 2007 Reprinted 2007, 2008, 2011

Science Press

Private Bag 7023 Marrickville NSW 1475 Australia Tel: (02) 9516 1122 Fax: (02) 9550 1915

[email protected] www.sciencepress.com.au

All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, recording or otherwise, without the prior permission of Science Press. ABN 98 000 073 861

Contents

Introduction

v

Verbs to Watch

vi

Dot Points

Moving About

vii

The World Communicates

ix

Electrical Energy in the Home

xi

The Cosmic Engine

xiii

Questions

Moving About

1

The World Communicates

45

Electrical Energy in the Home

77

The Cosmic Engine

113

Answers

Moving About

147

The World Communicates

157

Electrical Energy in the Home

167

The Cosmic Engine

179

Appendix

Data Sheet

187

Formula Sheet

188

Notes

... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ...

Introduction

What the book includes

,QWKLVERRN\RXZLOO¿QGW\SLFDOH[DPLQDWLRQTXHVWLRQVDQGDQVZHUVIRUHDFKGRWSRLQWLQWKH%RDUGRI6WXGLHV

syllabus for each topic in the Year 11 Physics course:

‡

0RYLQJ$ERXW

‡

(OHFWULFLW\LQWKH+RPH

‡

7KH:RUOG&RPPXQLFDWHV

‡

7KH&RVPLF(QJLQH

Also included are typical experimental results for students to analyse if the third column of the syllabus indicates

WKDWVWXGHQWVVKRXOGFDUU\RXWµ¿UVWKDQGLQYHVWLJDWLRQV¶

Format of the book

The book has been formatted in the following way:

1. Main topic statement (column 1 of syllabus)

1.1

etc Syllabus requirement from columns 2 and 3.

1RWHWKDWWKHQXPEHULQJRIWKHVHUHTXLUHPHQWVLVWKHDXWKRU¶VFKRLFHDQGKDVEHHQXVHGWRPDNHUHIHUHQFLQJ

TXHVWLRQVDQGDQVZHUVFOHDUHU7KHLQGLYLGXDOUHTXLUHPHQWVDUHQRWQXPEHUHGLQWKHV\OODEXVWKH\DUHVLPSO\

EXOOHWHG±KHQFHRXUXVHRIµGRWSRLQWV¶ZKHQZHUHIHUWRWKHP

1.1.1 )LUVWW\SLFDOTXHVWLRQZKLFKFRXOGEHDVNHGLQDQH[DPLQDWLRQIRUWKLVV\OODEXV



UHTXLUHPHQW

1.1.2 6HFRQGW\SLFDOTXHVWLRQZKLFKFRXOGEHDVNHGLQDQH[DPLQDWLRQIRUWKLVV\OODEXV



UHTXLUHPHQWHWF

7KHQXPEHURIOLQHVSURYLGHGIRUHDFKDQVZHUJLYHVDQLQGLFDWLRQRIKRZPDQ\PDUNVWKHTXHVWLRQPLJKWEH

worth in an examination. As a rough rule, every two lines of answer might be worth one mark. Note that in any

DQVZHUVWKUHHOLQHVKDYHEHHQSURYLGHGDVWKHDPRXQWRIZULWLQJUHTXLUHGH[FHHGVWZROLQHVEXWWKHSK\VLFV

involved is worth only one mark.

How to use the book

&RPSOHWLQJDOOTXHVWLRQVZLOOSURYLGH\RXZLWKDVXPPDU\RIDOOWKHZRUN\RXQHHGWRNQRZIURPWKHV\OODEXV

You may have done work in addition to this with your teacher as extension work. Obviously this is not covered,

but you may need to know this additional work for your school exams.

:KHQZRUNLQJWKURXJKWKHTXHVWLRQVZULWHWKHDQVZHUV\RXKDYHWRORRNXSLQDGLIIHUHQWFRORXUWRWKRVH\RX

NQRZZLWKRXWKDYLQJWRUHVHDUFKWKHZRUN7KLVZLOOSURYLGH\RXZLWKDTXLFNUHIHUHQFHWRZRUN\RXVKRXOG

spend more time revising later, and allow you to spend your study time more productively.

account/account for

State reasons for, report on, give an account of,

narrate a series of events or transactions.

analyse

Identify components and the relationships among

them, draw out and relate implications.

apply

Use, utilise, employ in a particular situation.

appreciate

Make a judgement about the value of something.

assess

0DNHDMXGJHPHQWRIYDOXHTXDOLW\RXWFRPHV

results or size.

calculate

'HWHUPLQHIURPJLYHQIDFWV¿JXUHVRULQIRUPDWLRQ

clarify

Make clear or plain.

classify

Arrange into classes, groups or categories.

compare

Show how things are similar and different.

construct

Make, build, put together items or arguments.

contrast

Show how things are different or opposite.

critically (analyse/evaluate)

Add a degree or level of accuracy, depth, knowledge

DQGXQGHUVWDQGLQJORJLFTXHVWLRQLQJUHÀHFWLRQDQG

TXDOLW\WRDQDQDO\VLVRUHYDOXDWLRQ

deduce

Draw conclusions.

GH¿QH

6WDWHWKHPHDQLQJRIDQGLGHQWLI\HVVHQWLDOTXDOLWLHV

demonstrate

Show by example.

describe

Provide characteristics and features.

discuss

Identify issues and provide points for and against.

distinguish

Recognise or note/indicate as being distinct or

different from, note difference between things.

evaluate

Make a judgement based on criteria.

examine

,QTXLUHLQWR

explain

Relate cause and effect, make the relationship

between things evident, provide why and/or how.

extract

Choose relevant and/or appropriate details.

extrapolate

Infer from what is known.

identify

Recognise and name.

interpret

Draw meaning from.

investigate

3ODQLQTXLUHLQWRDQGGUDZFRQFOXVLRQVDERXW

justify

Support an argument or conclusion.

outline

Sketch in general terms; indicate the main features.

predict

Suggest what may happen based on available data.

propose

Put forward (a point of view, idea, argument,

suggestion etc) for consideration or action.

recall

Present remembered ideas, facts or experiences.

recommend

Provide reasons in favour.

recount

Retell a series of events.

summarise

Express concisely the relevant details.

synthesise

Put together various elements to make a whole.

Dot Point

Page

1.

Speed changes

2

1.1

Identify that a typical journey

involves speed changes.

2

1.2

Distinguish between average and

instantaneous

speed.

2

1.3

Distinguish between scalar and



YHFWRUTXDQWLWLHV



 'H¿QHDYHUDJHYHORFLW\DV

v

_av

 ǻrǻt

4

1.5

Compare instantaneous and

average speed and velocity.

4

1.6

Solve problems and analyse

information

using:

v

_av

 ǻrǻt

5

 3HUIRUPD¿UVWKDQGLQYHVWLJDWLRQWR

measure average speed of an object.

6

1.8

Graph displacement vs. time data

for objects with uniform linear velocity.

8

1.9

Graph displacement vs. time data



IRUREMHFWVZLWKQRQXQLIRUPYHORFLW\



1.10 Present graphically velocity vs. time

data for objects with uniform linear

velocity.

11

1.11 Present graphically velocity vs. time



GDWDIRUREMHFWVZLWKQRQXQLIRUP

linear

velocity.

12

2.

Forces, acceleration and deceleration 13

2.1

Describe the motion of one body

relative to another.

13

2.2

Identify the usefulness of using

vector

diagrams.

13

2.3

Explain the need for a net external

force to act to change velocity.

14

2.4

Describe the actions that must be

taken for a vehicle to change

direction, speed up and slow down.

14

2.5

Describe effects of external forces

on bodies including friction and

air

resistance.

15

Dot Point

Page

 'H¿QHDYHUDJHDFFHOHUDWLRQDV

a

_av

ǻvǻt = (v – u)/t 15

2.8

Gather information about different

situations where acceleration is

positive and negative.

16

 'H¿QHWKHWHUPVPDVVDQGZHLJKW

with reference to effects of gravity.

16

2.10 Outline forces involved in causing

a change in the velocity of a vehicle.

17

 ,QWHUSUHW1HZWRQ¶V6HFRQG/DZRI



0RWLRQDQGUHODWHLWWRȈF = ma 18

2.12 Solve problems and analyse



LQIRUPDWLRQXVLQJȈF = ma 19

2.13 Identify the net force in a wide

variety of transport situations and



H[SODLQLWVFRQVHTXHQFHVLQWHUPVRI



1HZWRQ¶V6HFRQGODZ



2.14 Solve problems and analyse

information

involving:

F = mv

2

_/r

for vehicles travelling around curves.

24

 3HUIRUP¿UVWKDQGLQYHVWLJDWLRQVWR

show the relationship between force,

mass and acceleration.

26

2.16 Solve problems using vector



GLDJUDPVWR¿QGUHVXOWDQWYHORFLW\

acceleration and force.

28

 3HUIRUPD¿UVWKDQGLQYHVWLJDWLRQ

to demonstrate vector addition and

subtraction.

29

3.

Motion and energy changes 30

3.1

Identify that a moving object has

kinetic energy and that work done

on it can increase that energy.

30

3.2

Solve problems involving the kinetic

energy of vehicles and the work

done

using:

E

_k

= ½mv

2

_{and W = Fs 30}

3.3

Describe the energy transformations

that occur in collisions.

31

Dot Point

Page

3.4 Analyse

information to trace the energy

transfers and transformations in collisions

leading to irreversible distortions.

32

 'H¿QHWKHODZRIFRQVHUYDWLRQRIHQHUJ\



4.

Momentum 33

 'H¿QHPRPHQWXPDVp = mv 33

 'H¿QHLPSXOVHDVI = Ft 33

4.3

Explain conservation of momentum



LQWHUPVRI1HZWRQ¶V7KLUG/DZ



4.4

Solve problems and analyse data

using:

p = mv and I = Ft 33

4.5

Perform investigations to analyse

data for the change in momentum

in

collisions.

36

4.6

Solve problems to apply the law of

conservation of momentum to

describe the collision between a

moving and a stationary vehicle.

37

4.7

Solve problems to apply the law of

conservation of momentum to

describe the collision of a moving

vehicle with an immovable object.

37

4.8

Solve problems to apply the law of

conservation of momentum to the

collision between objects moving

in opposite directions.

38

Dot Point

Page

4.9

Solve problems to apply the law of

conservation of momentum to the

collision between objects moving

in the same direction.

38

5.

Safety devices 40

 'H¿QHWKHLQHUWLDRIDYHKLFOHDVLWV

tendency to remain in uniform

motion or at rest.

40

 $QDO\VH¿UVWRUVHFRQGKDQGGDWD

about the potential danger presented

by loose objects in a vehicle.

40

 'LVFXVVUHDVRQVZK\1HZWRQ¶V



)LUVW/DZRI0RWLRQLVQRWDSSDUHQW

in many real world situations.

41

5.4

Assess reasons for low speed zones



LQEXLOWXSDUHDVDQGWKHDGGLWLRQRI

airbags and crumple zones to vehicles

with respect to impulse and momentum.

41

5.5

Evaluate the effectiveness of some

safety features of motor vehicles.

42

 $VVHVVEHQH¿WVRIWHFKQRORJLHVIRU

avoiding or reducing the effect of a

collision.

43

Dot Point

Page

1.

The wave model and information

transfer 46

1.1

Describe the energy transformations

in one of: mobile telephone, fax or

modem, radio, TV (see 3.9).

46

1.2

Describe waves as a transfer of energy

that may occur in 1, 2, or 3 dimensions.

46

1.3

Identify that mechanical waves need

a medium while electromagnetic



ZDYHVGRQ¶W



 'H¿QHDQGDSSO\WKHWHUPVPHGLXP

displacement, amplitude, period,

compression, rarefaction, crest,

trough, transverse, longitudinal,



ZDYHVIUHTXHQF\ZDYHOHQJWKDQG

velocity to the wave model.

47

1.5

Describe the relationship between

particle motion and direction of

energy transfer in waves.

48

1.6

Draw diagrams for transverse and

longitudinal waves, directions of

particle movement and propagation.

48

1.7

Quantify the relationship between



YHORFLW\IUHTXHQF\DQGZDYHOHQJWK

Y IȜ 49

1.8

Perform an experiment to gather



LQIRUPDWLRQDERXWWKHIUHTXHQF\

and amplitude of waves.

50

1.9

Solve problems and analyse data

by

applying:

Y IȜ to a range of

situations.

50

1.10 Present and analyse information



IURPGLVSODFHPHQWWLPHJUDSKVIRU

transverse wave motion.

51

1.11 Perform an experiment to identify

the relationship between the



IUHTXHQF\DQGZDYHOHQJWKRID

sound wave at constant velocity.

53

1.12 Perform an experiment to observe

the transfer of waves in slinky springs,

water and ropes.

53

Dot Point

Page

2.

Sound waves 54

2.1

Identify that sound waves are

vibrations of particles in a medium.

54

2.2

Relate compressions and rarefactions

of sound waves to crests and troughs

of transverse waves.

54

 ([SODLQTXDOLWDWLYHO\WKDWSLWFKLV



UHODWHGWRIUHTXHQF\DQGYROXPHWR

amplitude of sound waves.

54

 ([SODLQDQHFKRDVDUHÀHFWLRQRID

sound

wave.

54

2.5

Describe the principle of superposition

and compare the resulting waves to the

original waves in sound.

55

2.6

Present graphs, solve problems and

analyse data for superposition of waves.

55

 3HUIRUPD¿UVWKDQGLQYHVWLJDWLRQWR

observe the superposition of two waves

using a CRO or computer.

56

 3HUIRUPD¿UVWKDQGLQYHVWLJDWLRQWR

analyse sound waves.

57

3.

Using the electromagnetic spectrum 58

3.1

Describe emr in terms of their speed

in space and their lack of need of a

medium for propagation.

58

3.2

Identify electromagnetic wavebands



¿OWHUHGRXWE\WKHDWPRVSKHUH



HVSHFLDOO\89;UD\VDQGȖUD\V



3.3

Identify methods for the detection

of various wave bands in the em

spectrum.

59

3.4

Explain the relationship between the

intensity of emr and the distance

from a source as an example of the



LQYHUVHVTXDUHODZ



 3HUIRUPD¿UVWKDQGLQYHVWLJDWLRQWR



PRGHOWKHLQYHUVHVTXDUHODZ



 2XWOLQHKRZDPSOLWXGHRUIUHTXHQF\

modulation of visible light, microwaves

and/or radio waves is used to transmit

Dot Point

Page

3.7

Analyse data to identify the em

spectrum range used in modern

communications.

61

3.8

Discuss problems produced by the

limited range of the em spectrum

available for communications.

62

1.1

Describe the energy transformations



UHTXLUHGLQRQHRIPRELOHWHOHSKRQH

fax or modem, radio, TV.

62

3.9

Analyse data to identify the waves

involved in the transfer of energy in

one of: mobile telephones, TV or radar.

63

4.

5HÀHFWLRQDQGUHIUDFWLRQRI

electromagnetic

waves 64

4.1

Describe and apply the law of



UHÀHFWLRQDQGH[SODLQWKHHIIHFWRI



UHÀHFWLRQIURPDSODQHVXUIDFHRQZDYHV 

4.2

Perform an experiment to observe

the path of light rays and draw

diagrams to show direction of travel

of light rays and wavefronts.

64

4.3

Present information using ray

diagrams to show the path of waves



UHÀHFWHGIURPYDULRXVVXUIDFHV



 'HVFULEHRQHDSSOLFDWLRQRIUHÀHFWLRQ

for various surfaces.

66

4.5

Describe ways in which applications

of light, radio and microwaves have

helped information transfer.

67

4.6

Explain that refraction is related to

the velocity of a wave in different

media and outline how this may

result in the bending of a wavefront.

67

Dot Point

Page

 'H¿QHUHIUDFWLYHLQGH[LQWHUPVRI

the changes in velocity of a wave in

passing from one medium to another.

68

 'H¿QH6QHOO¶V/DZ



4.9

Solve problems and analyse



LQIRUPDWLRQXVLQJ6QHOO¶V/DZ



4.10 Perform an investigation to graph

the angle of incidence and refraction

for light encountering a medium

change showing the relationship

between these angles.

71

 3HUIRUPD¿UVWKDQGLQYHVWLJDWLRQWR

calculate the refractive index of glass

or

perspex.

72

4.12 Identify the conditions necessary for



WRWDOLQWHUQDOUHÀHFWLRQZLWKUHIHUHQFH

to the critical angle.

73

 2XWOLQHKRZWRWDOLQWHUQDOUHÀHFWLRQ



LVXVHGLQRSWLFDO¿EUHV



5.

Technology and electromagnetic waves 75

5.1

Identify types of communication data

that are stored or transmitted in

digital

form.

75

5.2

Discuss some of the physical

principles used in one application of

physics related to waves in one of the

following: GPS, CD technology, DVD

technology, the Internet.

76

Dot Point

Page

1.

History of electricity 78

1.1

Discuss how the main sources of domestic

energy have changed over time.

78

1.2

Assess some of the impacts of changes

in, and increased access to, sources

of

energy.

78

1.3

Discuss some of the ways on which

electricity can be provided in remote

locations.

79

1.4

Analyse differing views of Volta and

Galvani on animal and chemical electricity. 79

1.5

Discuss whether their (Volta and

Galvani) different views contributed

to increased understanding of electricity.

81

2.

Electricity and electric circuits 82

2.1

Describe the behaviour of electrostatic

charges.

82

2.2

Describe the behaviour of



HOHFWURVWDWLF¿HOGV



2.3

Present diagrams to describe electric



¿HOGVWUHQJWKDQGGLUHFWLRQEHWZHHQ

parallel

plates.

83

2.4

Present diagrams to describe electric



¿HOGVWUHQJWKDQGGLUHFWLRQDERXWDQG

between positive and negative point

charges.

84

 'H¿QHWKHXQLWRIHOHFWULFFKDUJHDV

the

coulomb.

84

 'H¿QHHOHFWULF¿HOGDVD¿HOGRIIRUFH



ZLWKVWUHQJWKHTXDOWRWKHIRUFHSHU

unit charge at that point, i.e. E = F/Q 85

2.7

Solve problems and analyse information

using:

E = F/Q 85

 'H¿QHHOHFWULFFXUUHQWDVWKHUDWHDW



ZKLFKFKDUJHÀRZVXQGHUWKHLQÀXHQFH



RIDQHOHFWULF¿HOG



2.9

Identify that current can be either

direct or alternating.

87

2.10 Describe electric potential difference

(voltage) between points as the change

Dot Point

Page

2.11 Discuss how potential difference

changes at points around a circuit.

88

2.12 Perform an experiment to show how

potential difference varies between

points in a circuit (also 3.3).

89

2.13 Perform an experiment to show the

relationship between voltage across,

and current in, a circuit (also 3.3).

90

2.14 Solve problems and analyse

information

using:

R = V/I 91

2.15 Identify differences between conductors

and

insulators.

92

 'H¿QHUHVLVWDQFHDVWKHUDWLRRIYROWDJH

to current for a particular conductor.

92

 'HVFULEHTXDOLWDWLYHO\KRZYDULRXV

factors affect the movement of

electricity through a conductor.

92

2.18 Identify materials used as conductors

to provide household electricity.

93

3.

Series and parallel circuits 95

3.1

Identify differences between series

and parallel circuits.

95

3.2

Compare parallel and series circuits

in terms of voltage across components

and current through them.

96

3.3

Perform experiments to compare

current and voltage in series circuits

(see 2.12 and 2.13).

97

 3HUIRUP¿UVWKDQGLQYHVWLJDWLRQVWR

compare measurements of current

and voltage in parallel circuits.

97

3.5

Identify uses of ammeters and voltmeters.

98

3.6

Explain why ammeters and voltmeters

are connected differently in a circuit.

98

3.7

Explain why there are different circuits

for lighting, heating and other

appliances in a house.

99

3.8

Construct a model to show household

circuits.

100

Dot Point

Page

4.

Electrical power 101

4.1

Explain that power is the rate at which

energy is transformed from one form

to

another.

101

4.2

Identify the relationship between

power, potential difference and current.

101

 3HUIRUPD¿UVWKDQGLQYHVWLJDWLRQWR

demonstrate the relationship between

current, voltage and power.

101

4.4

Explain why the kWh is used to

measure electrical energy consumption

rather than the joule.

103

4.5

Identify that the total amount of energy

used depends on the length of time



FXUUHQWLVÀRZLQJDQGFDQEH

calculated using: Energy = VIt 104

4.6

Solve problems using:

P = VI and Energy = VIt 104

5.

0DJQHWLF¿HOGV 106

5.1

Describe the behaviour of the magnetic

poles of bar magnets when they are

brought close together.

106

 'H¿QHWKHGLUHFWLRQRIWKHPDJQHWLF



¿HOGDWDSRLQWDVWKHGLUHFWLRQRI

force on a small north magnetic pole

when placed at that point.

106

5.3 Use and to show the direction

of current and and to show the



GLUHFWLRQRIDPDJQHWLF¿HOG



Dot Point

Page

 'HVFULEHWKHPDJQHWLF¿HOGDURXQG

pairs of magnetic poles.

106

5.5

Describe the production of a magnetic



¿HOGE\DQHOHFWULFFXUUHQWFDUU\LQJ

conductor and how the right hand



JULSUXOHFDQ¿QGWKHGLUHFWLRQRI



FXUUHQWDQG¿HOGOLQHV



 3HUIRUPD¿UVWKDQGLQYHVWLJDWLRQWR

build an electromagnet.

107

5.7

Compare the nature and generation



RIPDJQHWLF¿HOGVE\VROHQRLGVDQG

a bar magnet.

108

5.8

Perform an experiment to observe



PDJQHWLF¿HOGVDURXQGEDUPDJQHWV

straight conductors and solenoids.

108

5.9

Explain one application of magnetic



¿HOGVLQKRXVHKROGV



6.

Safety devices 110

6.1

Discuss the dangers of electric shock

from both 240 volt AC mains supply

and various DC voltages, from appliances,

on the muscles of the human body.

110

6.2 Describe

the

functions of circuit breakers,

fuses, earthing, double insulation and

other safety devices in the home.

110

Dot Point

Page

1.

Models of the Universe 114

1.1

Outline historical models of the

Universe from the time of Aristotle

to that of Newton.

114

1.2

Assess one model of the Universe

developed from the time of Aristotle

to the time of Newton to identify

limitations placed on the development

of each by available technology.

115

2.

Origins of the Universe 118

2.1

Describe probable origins of the

Universe.

118

2.2

Outline the discovery of the expansion

of the Universe by Hubble, following

its earlier prediction by Friedmann.

122

2.3

Describe the transformation of

radiation into matter following the

Big

Bang.

123

2.4

Identify that Einstein described the



HTXLYDOHQFHRIPDVVDQGHQHUJ\



2.5

Outline how the accretion of galaxies

and stars occurred through expansion

and cooling of the Universe,



VXEVHTXHQWORVVRISDUWLFOHNLQHWLF

energy, gravitational attraction of

particles, and lumpiness of gas clouds

that allows gravitational collapse.

124

3.

Stars and their life cycles 127

 'H¿QHWKHUHODWLRQVKLSEHWZHHQWKH

temperature of a body and the

dominant wavelength of the radiation

emitted from that body.

127

3.2

Identify that the surface temperature

of a star is related to its colour.

127

3.3

Relate the brightness of an object to

its luminosity and distance.

128

3.4

Solve problems to apply the inverse



VTXDUHODZRILQWHQVLW\RIOLJKWWRUHODWH

the brightness of a star to its luminosity

and distance from the observer.

131

Dot Point

Page

 'HVFULEHD+HUW]VSUXQJ5XVVHOO



GLDJUDPDVWKHJUDSKRIDVWDU¶V

luminosity against its colour or

surface

temperature.

133

 8VHWKH+HUW]VSUXQJ5XVVHOOGLDJUDP

to examine the variety of star groups



LQFOXGLQJ0DLQ6HTXHQFHUHGJLDQWV

and white dwarfs.

134

3.7

Identify energy sources characteristic

of each star group including Main



6HTXHQFHUHGJLDQWVDQGZKLWHGZDUIV



4.

The Sun 138

4.1

Identify that energy may be released

from the nuclei of atoms.

138

4.2

Describe the nature of emissions

from the nuclei of atoms as radiation

of alpha and beta particles and gamma

rays in terms of ionising power,

penetrating power, effect of magnetic



¿HOGHIIHFWRIHOHFWULF¿HOG



 3HUIRUPD¿UVWKDQGLQYHVWLJDWLRQWR

compare the penetrating power of

alpha, beta and gamma radiation.

139

4.4

Identify the nature of emissions

reaching Earth from the Sun.

140

4.5

Describe the particulate nature of the

solar

winds.

141

4.6

Outline the cyclic nature of sunspot

activity and its impact on Earth

through solar winds.

141

4.7

Describe sunspots as representing

regions of strong magnetic activity

and lower temperature.

142

4.8

Assess the effect of sunspot activity



RQ(DUWK¶VSRZHUJULGDQGVDWHOOLWH

communications.

143

Answers to The Cosmic Engine 179

Notes

... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ...

DOT POINT

1. Vehicles do not typically travel at a constant speed.

1.1

Identify that a typical journey involves speed changes.

1.1.1

Describe two speed changes which occur during typical journeys in a car and state one reason

for each change.

... ... ... ... ... ...

1.2

Distinguish between the average and instantaneous speed of vehicles and other bodies.

1.2.1

Compare average and instantaneous speed.

... ... ... ... ... ...

1.3

Distinguish between scalar and vector quantities in equations.

1.3.1

&RPSDUHVFDODUDQGYHFWRUTXDQWLWLHV

... ... ... ...

1.3.2

&RPSOHWHWKHWDEOHE\LGHQWLI\LQJ¿YHH[DPSOHVHDFKRIVFDODUDQGYHFWRUTXDQWLWLHV

Scalar quantities Vector quantities

1.3.3

Compare the distance travelled by an object with its displacement.

... ... ... ...

1.3.4

Three objects travel from X to Y by three different roads as shown in the diagram. Y is due

east of X.

X Y Road 1 = 75 km Road 3 = 150 km Road 2 = 50 km

Use the information to complete the table.

Object travelling by Distance travelled (km) Displacement (km) Road 1

Road 2 Road 3

1.3.5

Clarify the idea of expressing direction of travel as a bearing.

... ...

1.3.6

The diagram shows the paths taken by four wombats as they came out of their burrow to

search for food. The diagram is drawn to scale where 1 cm = 10 m.

Wombat 1 Wombat 2

Wombat 3

Wombat 4 N Ç

Use the information to complete the table.

Wombat Distance travelled (m) Displacement (m) (directions as compass readings)

Displacement (m) (directions as bearing) 1

 'H¿QHDYHUDJHYHORFLW\DV

av

r

t

1.4.1

,GHQWLI\WKHTXDQWLW\UHSUHVHQWHGE\ǻrLQWKHDERYHHTXDWLRQ

...

1.4.2

'H¿QHWKLVTXDQWLW\

... ... ...

1.5

Compare instantaneous and average speed with instantaneous and average velocity.

1.5.1

:ULWHDQHTXDWLRQ\RXFRXOGXVHWR¿QGWKHDYHUDJHVSHHGRIDQREMHFW

... ...

1.5.2

([SODLQKRZWKLVHTXDWLRQGLIIHUVIURPWKHRQHJLYHQLQDERYH

... ... ...

1.5.3

Identify the essential difference between instantaneous speed and instantaneous velocity.

... ... ... ...

1.5.4

Identify the essential difference between average speed and average velocity.

... ... ... ...

1.5.5

A car takes 2.5 hours to travel along the 150 km road from X and Y as shown in the diagram

at a constant speed of 60 kph. X and Y are 120 km apart.

X P

Q

Y

D

&RPSDUHWKHFDU¶VLQVWDQWDQHRXVVSHHGDWSRLQWV3DQG4

... ...

E

&RPSDUHWKHFDU¶VLQVWDQWDQHRXVYHORFLW\DWSRLQWV3DQG4

... ...

F

&DOFXODWHWKHFDU¶VDYHUDJHVSHHGIRUWKHMRXUQH\

... ...

G

&DOFXODWHWKHFDU¶VDYHUDJHYHORFLW\IRUWKHMRXUQH\

... ...

 6ROYHSUREOHPVDQGDQDO\VHLQIRUPDWLRQXVLQJ

_av

r

t

1.6.1

A swimmer dives from the blocks into the pool and races 50 m to the other end of the pool.

This takes her 32.6 s.

(a)

Calculate her average speed.

... ...

(b)

Calculate her average velocity.

... ...

1.6.2

/DWHULQWKHPHHWWKHVDPHVZLPPHUVZLPVLQWKHPHYHQW7KLVWDNHVKHUV

(a)

Calculate her average speed.

... ...

(b)

Calculate her average velocity.

... ...

1.6.3

Consider three cars travelling from X to Y along three roads shown. Y is due east of X.

X Y Road 1 = 120 km

Road 3 = 200 km Road 2 = 90 km

Use this information to complete the table.

Car travelling by Distance travelled (km) Displacement (km) Time taken (hr) Average speed of cars (kph) Average velocity of cars (kph) Road 1 3.0 Road 2 2.0 Road 3 5.0

 3HUIRUPD¿UVWKDQGLQYHVWLJDWLRQWRPHDVXUHWKHDYHUDJHVSHHGRIDQREMHFW

1.7.1

In an experiment, a ball was rolled down a ramp from rest, from various starting positions as

shown in the diagram. The results of the experiment are shown in the table.

P Q R S T Starting position Distance up the slope (m)

Time to roll down slope (s)

Average time to roll down slope (s) Average speed down slope (m s–1₎ Average speed squared (m2 _s–2₎ P 1.0 0.64 0.65 0.63 Q 1.5 0.76 0.79 0.79 R 2.0 0.92 0.91 0.87 S 2.5 1.03 0.99 1.01 T 3.0 1.14 1.09 1.10

(a)

Complete the table by calculating values for the missing data (to 2 decimal places).

(b)

If you were to draw a graph to show the relationship between the distance the object started

up the slope and its average speed as it rolled down the slope, identify the:

independent

variable

...

(c)

Draw this graph.

(d)

What conclusion can be made from this graph?

... ... ... ... ...

(e)

Explain your answer.

... ... ...

(f)

Calculate appropriate values and write them in

the last column of the results table and then use

these to draw another graph which will enable

you to make a conclusion for the experiment.

(g)

Write your conclusion for the experiment based

on this second graph.

... ... ... ... ... ...

(h)

Use your graph to predict the average speed of the ball if it was rolled down the slope from a

1.25 m starting position.

... ... ...

1.8

Present information graphically of displacement vs. time for objects with uniform linear

velocity.

1.8.1

Consider the following graph

representing the motion of a car.

(a)

How far did the car travel in the

¿UVWV"

...

(b)

Determine its change in displacement.

...

(c)

Calculate the average velocity of the car.

... ...

(d)

Determine the velocity of the car at time 8 s.

...

(e)

Predict the velocity of the car at time 30 s.

...

1.8.2

Consider the following graph

representing the motion of a car.

(a)

How far did the car travel in the

¿UVWV"

...

(b)

Determine its change in displacement.

...

(c)

Calculate the average velocity of the car.

... ...

(d)

Determine the velocity of the car at time 8 s.

...

(e)

Describe the journey of the car.

... ... ... 0 5 10 15 20 0 5 10 15 20 Time (s) Displacement (m north) 0 5 10 15 20 25 0 5 10 15 20 Time (s) Displacement (m north)

1.8.3

Consider the following graph

representing the motion of a car.

D

+RZIDUGLGWKHFDUWUDYHOLQWKH¿UVW

10 s?

...

(b)

Calculate the average speed of the

car.

...

(c)

Calculate the average velocity of the car.

... ...

(d)

Determine its displacement after 16 s.

... ...

(e)

Determine the velocity of the car at time 8 s.

...

 3UHVHQWLQIRUPDWLRQJUDSKLFDOO\RIGLVSODFHPHQWYVWLPHIRUREMHFWVZLWKQRQXQLIRUPOLQHDU

velocity.

1.9.1

Consider the following graph

representing the motion of a car.

D

+RZIDUGLGLWWUDYHOLQWKH¿UVWV"

...

(b)

Determine its total displacement.

...

(c)

Calculate the average velocity of the car.

... ...

(d)

Determine the velocity of the car at time 12.5 s.

...

(e)

Describe the journey of the car.

-20 -10 0 10 20 5 10 15 20 Time (s) Displacement (m north)

0 10 20 30 40 50 60 0 5 10 15 20 Time (s) Displacement (m north)

1.9.2

Consider the following graph

representing the motion of a car.

D

+RZIDUGLGWKHFDUWUDYHOLQWKH¿UVWV"

...

(b)

Determine its total displacement.

...

(c)

Calculate the average speed of the car.

... ...

(d)

Calculate the average velocity of the car.

... ...

(e)

Determine the velocity of the car at time 3 s.

... ...

1.9.3

Consider the following graph representing the motion of a car.

D

+RZIDUGLGWKHFDUWUDYHOLQWKH¿UVW

12 s?

...

(b)

Determine its total displacement.

...

(c)

Calculate the average speed of the

car.

... ...

(d)

Calculate the average velocity of the car.

... ...

(e)

Determine the velocity of the car at time 15 s.

... ... -40 -30 -20 -10 0 10 20 30 40 5 10 15 20 Time (s) Displacement (m north) -60 -40 -20 0 20 40 60 80 5 10 15 20 Time (s) Displacement (m north)

1.10 Present information graphically of velocity vs. time for objects with uniform linear velocity.

1.10.1 Consider the following graph

representing the motion of a car.

(a)

How far did the car travel in 20 s?

...

(b)

Find its displacement after 10 s.

...

(c)

Calculate the average velocity

of the car.

... ...

(d)

Calculate the acceleration of the car.

... ...

1.10.2 Consider the following graphs representing the motion of four cars.

-20 -15 -10 -5 0 5 10 15 20 10 15 20 Time (s) Ve lo c it y ( m /s n o rt h ) A B C D 5

Use this information to complete the table.

Car Average speed (m s–1₎ Average velocity (m s–1₎ Acceleration (m s–2₎ Displacement after 10 s A B C D -18 -12 -6 0 6 12 18 5 10 15 20 Time (s) Velocity (m/s east)

 3UHVHQWLQIRUPDWLRQJUDSKLFDOO\RIYHORFLW\YVWLPHIRUREMHFWVZLWKQRQXQLIRUPOLQHDUYHORFLW\

1.11.1 Consider the following graph representing the motion of a car.

(a)

How far did the car travel in 20 s?

...

(b)

Calculate the average velocity of the

car.

...

(c)

Calculate the acceleration of the car

at time 12 s.

... ... ...

(d)

Calculate the average acceleration of the car.

... ...

1.11.2 Consider the following graph representing the motion of a car.

(a)

How far did the car travel in 20 s?

...

(b)

Calculate its displacement at time 20 s.

...

(c)

Calculate the average speed of the car.

... ... ...

(d)

Calculate the average velocity of the car.

... ... ...

(e)

Determine the acceleration of the car at times 3, 7 and 16 s.

... ... 0 10 20 30 40 50 60 0 5 10 15 20 Time (s) Velocity (m/s north) -10 -5 0 5 10 15 0 5 10 15 20 Time (s) Velocity (m/s south)

2.

An analysis of the external forces on vehicles helps us understand the effects of

acceleration and deceleration.

2.1

Describe the motion of one body relative to another.

2.1.1

Object X is moving east at 30 m s

–1

_{. Object Y is moving west at 25 m s}

–1

_{. Object Z is}

moving east at 15 m s

–1

_{. Calculate the velocity of:}

(a)

X relative to Y

...

(b)

X relative to Z

...

(c)

Y relative to X

...

(d)

Y relative to Z

...

(e)

Z relative to X

...

(f)

Z relative to Y

...

2.1.2

From your answers above, identify the relationship between the velocity of object A relative

to object B and the velocity of object B relative to object A.

... ...

2.1.3

A person can row a boat at 1.75 m s

–1

_{LQVWLOOZDWHU+HURZVRQDULYHUZKLFKÀRZVDW}

0.45 m s

–1.

_{Calculate the velocity of the person relative to the banks of the river if he rows:}

D

ZLWKWKHÀRZ

...

E

DJDLQVWWKHÀRZ

...

Calculate the velocity of the boat relative to the water if he rows:

F

ZLWKWKHÀRZ

...

G

DJDLQVWWKHÀRZ

...

2.2

Identify the usefulness of using vector diagrams to assist in solving problems.

2.2.1

Object X is moving east at 24 m s

–1

_{. Object Y is moving north at 18 m s}

–1

_{. With the aid of an}

appropriate vector diagram, calculate the velocity of:

(a)

X relative to Y

... ... ... ... ... ...

(b)

Y relative to X

... ... ... ... ... ... ... ...

2.3

Explain the need for a net external force to act in order to change the velocity of an object.

2.3.1

5HFDOO1HZWRQ¶V)LUVW/DZRI0RWLRQ

... ... ...

2.3.2

*LYHDQH[DPSOHRI1HZWRQ¶V)LUVW/DZRI0RWLRQ

... ... ...

2.3.3

Describe a situation where an object is travelling with constant speed and yet its velocity is

constantly changing.

... ...

2.3.4

Describe the force acting on the object in 2.3.3 above.

... ...

2.4

Describe the actions that must be taken for a vehicle to change direction, speed up and slow

down.

2.4.1

Identify what is needed to change the direction or speed of an object.

... ...

2.4.2

What is an object doing if its speed is changing?

... ...

2.4.3

&ODULI\WKHWHUPVµSRVLWLYH¶DQGµQHJDWLYH¶IRUFHDVWKH\DUHXVHGLQ3K\VLFV

... ... ... ...

2.5

Describe the typical effects

of external forces on bodies

including friction and air

resistance.

2.5.1

A car travels along a

straight road at constant

speed. Draw a diagram

to show all the forces

acting on it.

2.5.2

Describe what each of these forces does to the car.

... ... ... ...

2.5.3

What is the net force on the car? Explain how you determine this.

... ...

2.6

Analyse the effects of external forces operating on a vehicle.

2.6.1

Identify three changes a force acting on a vehicle can cause to its motion.

... ... ...

 'H¿QHDYHUDJHDFFHOHUDWLRQDV



a

_av

= ǻv/ǻt = (v – u)/t

2.7.1

'H¿QHDFFHOHUDWLRQ

... ...

2.7.2

A force acts on a car for 4.0 s to increase its velocity from 5 m s

–1

_{to 25 m s}

–1

_{. Calculate the}

acceleration of the car.

2.7.3

A car accelerates at 4.0 m s

–2

IRUV&DOFXODWHLWV¿QDOYHORFLW\

(a)

if its initial velocity was 2.0 m s

–1

_{in the same direction as the force}

... ... ... ...

(b)

if its initial velocity was 3.5 m s

–1

_{in the opposite direction to the force}

... ... ...

 *DWKHU¿UVWKDQGLQIRUPDWLRQDERXWGLIIHUHQWVLWXDWLRQVZKHUHDFFHOHUDWLRQLVSRVLWLYHDQG

negative.

2.8.1

&ODULI\WKHFRQFHSWVRIµSRVLWLYH¶DQGµQHJDWLYH¶DFFHOHUDWLRQV

... ... ...

2.8.2

Identify three different situations where the acceleration of a car would be considered to be

positive.

... ... ...

2.8.3

Identify three different situations where the acceleration of a car would be considered to be

negative.

... ... ...

 'H¿QHWKHWHUPVPDVVDQGZHLJKWZLWKUHIHUHQFHWRWKHHIIHFWVRIJUDYLW\

2.9.1

'H¿QHPDVV

...

2.9.2

'H¿QHZHLJKW

... ...

2.9.3

Complete the table by comparing various properties of mass and weight.

Mass Weight

 2XWOLQHWKHIRUFHVLQYROYHGLQFDXVLQJDFKDQJHLQWKHYHORFLW\RIDYHKLFOHZKHQ

2.10.1 It is coasting on a horizontal surface with no pressure on the accelerator.

... ... ...

2.10.2 The car is moving on a horizontal surface with the driver pressing on the accelerator.

... ... ...

2.10.3 The car is moving on a horizontal surface with the driver pressing on the brakes.

... ... ...

2.10.4 The vehicle is passing over an icy patch on a horizontal road.

... ... ...

2.10.5 The vehicle is climbing a hill.

... ... ...

2.10.6 The vehicle is descending a hill.

2.10.7 The vehicle is following a curve on a horizontal road.

... ... ...

 ,QWHUSUHW1HZWRQ¶V6HFRQG/DZRI0RWLRQDQGUHODWHLWWR

ȈF = ma

2.11.1 5HFDOO1HZWRQ¶V6HFRQG/DZRI0RWLRQ

... ... ... ...

2.11.2 A car is accelerating uniformly along a road. Sketch graphs on the axes below to show the

relationships indicated.

F t v t r t

2.11.3 Forces act on several cars of different masses to produce identical accelerations. Sketch

graphs on the axes below to show the relationships indicated.

F m ǻv m ǻr m

2.11.4 Forces act on several cars of different masses to produce identical velocity changes. Sketch

graphs on the axes below to show the relationships indicated.

F m a m ǻr m

 6ROYHSUREOHPVDQGDQDO\VHLQIRUPDWLRQXVLQJ

ȈF = ma

2.12.1 Calculate the force acting on a 5.0 kg mass which accelerates for 3.0 s. During this time its

velocity changes from 2.5 m s

–1

_{east to 17.5 m s}

–1

_west.

... ... ... ...

2.12.2 A 12 N force acts on a body and accelerates it from rest to 4.5 m s

–1

_{south. This takes 15 s.}

Calculate the mass of the body.

... ... ... ...

2.12.3 An 80 g object is initially at rest. A 0.16 N force to the north acts on it for 5 s. Calculate:

(a)

the acceleration produced by the force

... ...

E

WKH¿QDOYHORFLW\RIWKHREMHFW

... ...

(c)

its displacement after 5 s

... ...

2.13 Identify the net force in a wide variety of situations involving modes of transport and explain

the consequences of that net force in terms of Newton’s Second law of Motion.

Note that the syllabus says ‘a wide variety of situations’. If you have not studied the examples given

here in class, then you don’t have to do them.

2.13.1 Consider the two blocks shown in the diagram. They are resting on a surface which provides

a frictional force of 0.25 N kg

–1

_.

2.5 kg 5.5 kg

18 N

X

(a)

Calculate the acceleration of the system.

... ...

(b)

Calculate the net force on each block.

... ...

(c)

Calculate the force block X puts on block Y.

... ...

(d)

Calculate the force block Y puts on block X.

... ...

2.13.2 Consider the two blocks shown in the diagram. They are resting on a smooth surface.

3.0 kg 6.0 kg

36 N

X

Y

string

(a)

Calculate the acceleration of the system.

... ...

(b)

Calculate the net force on each block.

... ...

(c)

Calculate the force tension in the string.

... ...

2.13.3 Consider the object shown in the diagram.

Several forces act on this object which is at rest

on a smooth, horizontal surface.

4 kg 26 N

15 N

(a)

Calculate the net force on the object.

... ... ... ... ... ... ... ...

(b)

Calculate the acceleration of the object.

... ...

(c)

Calculate its velocity after 5.0 s.

... ...

(d)

Calculate its displacement after 5 s.

... ...

2.13.4 Consider the two blocks shown in the diagram. They are connected by a light string over a

frictionless pulley.

D

/DEHODOOWKHIRUFHVDFWLQJLQWKLVSXOOH\V\VWHP

(b)

Calculate the acceleration of the system.

... ... ... ... ...

(c)

Calculate the net force on each block.

...

...

(d)

Calculate the tension in the string connecting the blocks.

... 2 kg

4 kg X

2.13.5 Consider the two blocks

shown in the diagram. They

are connected by a light

string over a frictionless

pulley. Block X is resting

on a smooth surface.

D

/DEHODOOWKHIRUFHVDFWLQJLQ

this pulley system.

(b)

Calculate the acceleration of the system.

... ... ... ...

(c)

Calculate the net force on each block.

... ...

(d)

Calculate the tension in the string connecting the blocks.

... ... ... ...

2.13.6 A 3 kg mass is resting on a Newton balance in an elevator. Complete the table to show the

reading on the balance in each of the following situations.

Movement of elevator Reading on Newton balance (a) Stationary

(b) Moving up at 2.0 m s–1

(c) Moving down at 2.0 m s–1

(d) Moving up at 2.0 m s–2

(e) Moving down at 2.0 m s–2

X

Y 2 kg

2.13.7 Two masses are connected by a string and are hanging from

the ceiling of an elevator as shown. Complete the table to

show the tensions in each string in the following situations.

Movement of elevator Tension in String 1 (N) Tension in String 2 (N) (a) Stationary (b) Moving up at 3.0 m s–1 (c) Moving down at 3.0 m s–1 (d) Moving up at 3.0 m s–2

(e) Moving down at 3.0 m s–2

2.13.8 A ball is hanging by a string from the ceiling of a bus.

Describe the motion of the bus when the string is:

(a)

hanging straight down

...

(b)

hanging down towards the rear of the bus

...

(c)

hanging down towards the front of the bus

...

2.13.9 A 3.0 kg ball is hanging by a string from the ceiling of a bus as

shown in the diagram.

D

/DEHOWKHIRUFHVDFWLQJRQWKHEDOO

(b)

Using an appropriate vector diagram, calculate the tension in the

string when the ball is in the position shown.

... ... ... ...

(c)

Calculate the acceleration of the bus.

... ... ... ...

(d)

See over page.

String 1 4 kg String 2 6 kg 10° 3 kg ball

(d) At what angle would the ball and string hang if the bus was

braking at 2.5 m s

–2

_?

... ... ... ... ... ... ... ... ... ... ... ...

 6ROYHSUREOHPVDQGDQDO\VHLQIRUPDWLRQLQYROYLQJ

F = mv

2

_/r

_{for vehicles travelling}

around curves.

2.14.1 Two 60 kg boys on 20 kg bikes are riding at 15 m s

–1

_{directly towards a wall which is 30 m}

from them. X continues towards the wall, but slams on his brakes applying a 400 N force.

Y does not put on his brakes, but turns his bike with the same force in a circular path in the

hope of not hitting the wall.

Analyse this information to determine whether or not the boys hit the wall.

For X

For Y

... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ...

2.14.2 A toy racing car of mass 150 g is racing around a circular track of diameter 80 cm. It takes

8.4 s to do one lap of the track. Calculate:

(a)

the speed of the car

... ... ...

(a)

the acceleration of the car

... ... ...

(b)

the centripetal force acting on the car

... ...

2.14.3 A 1500 kg racing car goes around a circular track of radius 200 m at a constant speed of 270 kph.

(a)

Calculate the speed of the car in m s

–1

_.

... ...

(b)

Calculate the acceleration of the car.

... ... ... ...

(c)

What force holds the car to the road as it speeds around this corner.

... ...

(d)

Calculate the value of this force.

... ...

(e)

State the direction this force acts.

... ...

 3HUIRUP¿UVWKDQGLQYHVWLJDWLRQVWRVKRZWKHUHODWLRQVKLSEHWZHHQIRUFHPDVVDQGDFFHOHUDWLRQ

2.15.1 Experiment

1

In this experiment, a trolley of

mass 1.5 kg was placed on the

bench accelerated by a force

attached to it by a string, which

passed over a pulley. The mass

of the trolley was kept constant

and different forces used to

accelerate it from rest across the

bench top. The time it took the

trolley to travel 1.0 m across the

benchtop was measured. The

results are shown in the table.

Run Accelerating Force (N) Time to travel 1.0 m (s) Initial speed of trolley (m s–1₎ Average speed of trolley (m s–1₎ Final speed of trolley (m s–1₎ Acceleration of trolley (m s–2₎ 1 1 F 0.89 2 2 F 0.63 3 3 F 0.52 4 4 F 0.45 5 5 F 0.40

(a)

Complete the table by calculating values for all missing data.

(b)

Draw a graph to show the relationship between the force and acceleration produced. (Place

force on the yD[LV

(c)

Use your graph to write a conclusion for the experiment.

... ...

Trolley Pulley

2.15.2 Experiment 2

The students did another experiment using the same apparatus. This time they kept the

accelerating force constant, and changed the mass of the trolley. They measured how long it

took the trolley to move 1.0 m across the benchtop.

Run Trolley mass (kg) Time to travel 1.0 m (s) Initial speed of trolley (m s–1₎ Average speed of trolley (m s–1₎ Final speed of trolley (m s–1₎ Acceleration of trolley (m s–2₎ (Acceleration)–1 1 1.0 1.83 2 2.0 2.58 3 3.0 3.16 4 4.0 3.65 5 5.0 4.08

(a)

Complete the table of results by

calculating values for all missing

TXDQWLWLHV

(b)

Graph mass vs. (acceleration)

–1

_.

(c)

Use your graph to write a conclusion for

the experiment.

... ... ...

...

Combining your conclusions for Experiments 1 and 2

G

8VHWKHFRQFOXVLRQV\RXKDYHZULWWHQWRZULWHDPDWKHPDWLFDOHTXDWLRQZKLFKVKRZVWKH

relationship between the mass of an object, the force acting on it, and the acceleration the

force produces.

...

H

8VHWKHUHVXOWVRIWKHH[SHULPHQWVWR¿QGWKHYDOXHRIWKHDFFHOHUDWLQJIRUFHVLQWKHWZR

experiments above.

Experiment 1

... ...

Experiment 2

... ...

2.16 Solve problems using vector diagrams to determine resultant velocity, acceleration and force.

2.16.1 A 2.5 kg object moving at 5.0 m s

–1

_{east is acted upon by a force which changes its velocity to}

12 m s

–1

_{south over a period of 4 s. By drawing an appropriate vector diagram, calculate:}

(a)

the change in velocity of the object

... ...

(b)

the acceleration of the object

... ... ... ...

(c)

the force that acted on the object

... ...

2.16.2 The velocity of an object changes from 6.0 m s

–1

_{west to 8.0 m s}

–1

_{north when a force of 12 N}

acts on it for 1.25 s. By drawing an appropriate vector diagram, calculate:

(a)

the change in velocity of the object

... ...

(b)

the acceleration of the object

... ... ... ...

(c)

the direction of the force that acted on the object

... ...

(d)

the mass of the object

... ...

 3HUIRUPD¿UVWKDQGLQYHVWLJDWLRQWRGHPRQVWUDWHYHFWRUDGGLWLRQDQGVXEWUDFWLRQ

2.17.1 A group of students set up the following apparatus to investigate the addition of vectors. They

hung masses on mass carriers to produce forces F

₁

and F

₂

on the ends of a long string, then

placed a third mass carrier and masses, F

₃

on the string between the pulleys. They adjusted

WKHPDVVHVRQHDFKFDUULHUXQWLOWKHV\VWHPZDVLQHTXLOLEULXPWKHQPHDVXUHGDQJOHș. Their

results for three sets of forces are shown in the table.

F₁ F₂ F₃ ș

60 g 90 g 132 g 59°

40 g 70 g 95 g 68°

45 g 55 g 70 g 93°

By drawing appropriate vector diagrams, show that these results are consistent with F

₃

being the

resultant of F

₁

and F

₂

.

F₁

F₃

F₂

3.

Moving vehicles have kinetic energy and energy transformations are an important aspect

in understanding motion.

3.1

Identify that a moving object possesses kinetic energy and that work done on that object can

increase that energy.

3.1.1

Explain, in terms of the law of conservation of energy, the relationship between the work

done on a falling object and its kinetic energy.

... ... ... ...

3.2

Solve problems and analyse information to determine the kinetic energy of vehicles and the

ZRUNGRQHXVLQJ

E

_k

= ½mv

2

_{and W = Fs}

3.2.1

A 12 kg car, at rest, is acted upon by a force acting towards the north, for 5 s. This changes its

kinetic energy by 2400 J.

(a)

Calculate the work done on the object by the force.

...

E

&DOFXODWHWKH¿QDOYHORFLW\RIWKHREMHFW

... ... ... ...

(c)

Calculate how far the object moves while the force is acting on it.

... ... ... ...

(d)

Calculate the acceleration of the object.

... ...

(e)

Calculate the magnitude of the force acting on the object.

... ... ...

3.2.2

If the car in Question 3.2.1 had been moving at 10 m s

–1

_{south initially, and the same force}

acted on it for the same time, calculate:

(a)

the initial kinetic energy of the car

... ... ...

E

WKH¿QDOYHORFLW\RIWKHFDU

... ... ...

F

WKH¿QDONLQHWLFHQHUJ\RIWKHFDU

... ...

(d)

the displacement of the car during the 5 seconds

... ...

H

*LYHQWKDWWKHZRUNGRQHLVHTXDOWRWKHFKDQJHLQHQHUJ\RIWKHFDUFDOFXODWHWKHZRUNGRQH

on the car by the force.

... ... ...

(f)

Account for your answer to (e).

... ... ... ...

3.3

Describe the energy transformations that occur in collisions.

3.3.1

A car of mass 1000 kg is moving at 15 m s

–1

_{when the driver loses control and it runs off the}

road, slamming into a tree and stopping.

(a)

Calculate the initial kinetic energy of the car.

... ... ...