2020 systems engineering written examination
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SUPERVISOR TO ATTACH PROCESSING LABEL HEREVictorian Certificate of Education 2020
STUDENT NUMBER
Letter
SYSTEMS ENGINEERINGWritten examination
Monday 30 November 2020 Reading time: 9.00 am to 9.15 am (15 minutes) Writing time: 9.15 am to 10.45 am (1 hour 30 minutes)
QUESTION AND ANSWER BOOK
Structure of bookSection Number of
questionsNumber of questions
to be answeredNumber of
marks
A 20 20 20B 15 15 80
Total 100
• Studentsarepermittedtobringintotheexaminationroom:pens,pencils,highlighters,erasers,sharpeners,rulersandonescientificcalculator.
• StudentsareNOTpermittedtobringintotheexaminationroom:blanksheetsofpaperand/orcorrectionfluid/tape.
Materials supplied• Questionandanswerbookof28 pages• Detachableinsertofmiscellaneousformulasinthecentrefold• Answersheetformultiple-choicequestions
Instructions• Writeyourstudent numberinthespaceprovidedaboveonthispage.• Checkthatyourname andstudent numberasprintedonyouranswersheetformultiple-choice
questionsarecorrect, andsignyournameinthespaceprovidedtoverifythis.• Unlessotherwiseindicated,thediagramsinthisbookarenotdrawntoscale.• AllwrittenresponsesmustbeinEnglish.
At the end of the examination• Placetheanswersheetformultiple-choicequestionsinsidethefrontcoverofthisbook.• Youmaykeepthedetachedinsert.
Students are NOT permitted to bring mobile phones and/or any other unauthorised electronic devices into the examination room.
©VICTORIANCURRICULUMANDASSESSMENTAUTHORITY2020
2020SYSENGEXAM 2
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Question 1Theleverinthediagramshownbelowisusedtoliftaloadof400N.
load = 400 N
1 m3 m
lever
ThemechanicaladvantageoftheleverisA. 4B. 3C. 0.33D. 0.25
Question 2
brown
black
green
gold
Whatisthevalueoftheresistorshowninthediagramabove?A. 1kΩB. 10kΩC. 1MΩD. 100kΩ
SECTION A – Multiple-choice questions
Instructions for Section AAnswerall questionsinpencilontheanswersheetprovidedformultiple-choicequestions.Choosetheresponsethatiscorrect orthatbest answersthequestion.Acorrectanswerscores1;anincorrectanswerscores0.Markswillnotbedeductedforincorrectanswers.Nomarkswillbegivenifmorethanoneansweriscompletedforanyquestion.Unlessotherwiseindicated,thediagramsinthisbookarenotdrawntoscale.
3 2020 SYSENG EXAM
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Question 3
2 m
500 NP
The moment of the force F = 500 N about the point P in the diagram shown above isA. 2 N mB. 250 N mC. 500 N mD. 1000 N m
Question 4Which one of the following is a DC motor that moves in discrete steps?A. a dynamoB. an alternatorC. a stepper motorD. a brushless motor
Question 5A schematic diagram for an electronic circuit is shown below.
20 Ω
40 Ω 40 Ω
A1 A2
40 V
The electric current through ammeters A1 and A2 is respectivelyA. IA1
= 1 A and IA2 = 1 A
B. IA1 = 1 A and IA2
= 0.5 A C. IA1
= 0.5 A and IA2 = 0.5 A
D. IA1 = 0.5 A and IA2
= 0.25 A
2020 SYSENG EXAM 4
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Question 6A 4K7 resistor has a gold tolerance band. The expected range for this resistor isA. 3K76 to 5K64B. 4K23 to 5K17C. 4K47 to 4K94D. 4K61 to 4K79
Question 7The circuit below shows four load resistors that are connected to a 9 VAC power supply.
25 Ω20 Ω15 Ω10 Ω9 VAC
Which load resistor will dissipate the largest amount of energy in a 10-minute period?A. 10ΩB. 15ΩC. 20ΩD. 25Ω
Question 8Aschematicdiagramofasimpletransistoramplifiercircuitisshownbelow.
+6 V
input signal
RCR1
R2
RE
VoutputVinput
0 V
Toincreasetheefficiencyofthistransistoramplifiercircuit,whatmustbereduced?A. the size of the input signal VinputB. the size of the output signal VoutputC. thelossesinthetransistoramplifiercircuitD. thelengthoftimethatthetransistoramplifieroperates
5 2020 SYSENG EXAM
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Question 9The main purpose of using a three-dimensional (3D) modelling tool prior to fabricating and assembling the components of an engineering system is toA. ensure that the system is visually appealing.B. ensure compliance with occupational health and safety (OH&S) requirements.C. select the cheapest materials for fabricating components. D. identify potential issues or problems with the system design.
Question 10Whichoneofthefollowingisanexampleofatechnologicaldevelopmentusedbycoal-firedpowerstationsto reduce their environmental impact?A. burning off captured gasesB. using carbon capture and storageC. using brown coal instead of black coalD. applyingthin-filmsolarphotovoltaictechnology
Question 11The evaluation of a systems engineering solution involves an examination of its features and/or functions. Why is it necessary to conduct an evaluation of a systems engineering solution?A. to ensure that the solution looks goodB. to determine whether the solution will workC. to determine the cost effectiveness of the solutionD. todeterminehowwellthesolutionsatisfiesthedesignbrief
Question 12The forms of renewable energy that would be available in Victoria’s inland regions areA. wind,tidal,wave,hydro-electric.B. solar,hydro-electric,biomass,tidal.C. wind,solar,hydro-electric,biomass.D. solar,geothermal,wave,biomass.
2020 SYSENG EXAM 6
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Question 13Theelectricscootershowninthediagrambelowistravellingtotheright.Whenaccelerating,thewheelexertsaforceontheroad,asshown.
force of wheel on road
direction of movement
Which one of the following shows the direction of the corresponding action–reaction force according to Newton’s third law?
A.
B.
C.
D.
Question 14A shopper needs to go to a store one level up in a shopping centre and is carrying 10 kg of purchased items in a shopping bag. The shopper has three options for going up one level:• alift• asetofstairs• a20mramp
Which one of the following best describes the work that would be done on the shopping bag as the shopper goes up one level in the shopping centre?A. greatest for the stairsB. equal for all optionsC. greatest for the rampD. greatest for the lift
7 2020SYSENGEXAM
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Question 15Anoutputpistonandaninputpistonareconnectedinahydraulicsystem,asshowninthediagrambelow.Theoutputpistonhasadiameterof400mmandtheinputpistonhasadiameterof200mm.
output piston
input piston
200 mm400 mm
Ifaforceof100Nisappliedbytheinputpiston,whatistheforceontheoutputpiston,correcttothenearestnewton?A. 25NB. 50NC. 200ND. 400N
Question 16Thegearsystemshowninthediagrambelowisusedtochangetheplaneofdriveshafts.
ThistypeofgearsystemisknownasaA. bevelgear.B. spurgear.C. wormgear.D. compoundgear.
2020 SYSENG EXAM 8
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Question 17Twopulleys,AandB,areconnectedbyabelt,asshowninthediagrambelow.PulleyAhasadiameterof200mmandPulleyBhasadiameterof300mm.Anadditionalpulley,PulleyC,isusedasatensioner.Pulley C has a diameter of 100 mm.
A B
C
100 mm
300 mm200 mm
IfPulleyArotatesclockwiseat200revolutionsperminute(rpm),inwhatdirectionwillPulleyCrotateandat how many revolutions per minute?A. clockwise at 200 rpmB. clockwise at 400 rpmC. anticlockwise at 200 rpmD. anticlockwise at 400 rpm
Question 18The diagram below shows a rack and pinion gear.
What is the purpose of using a rack and pinion gear?A. changing clockwise motion to anticlockwise motionB. changing linear motion to rotational motionC. increasing torqueD. decreasing torque
9 2020 SYSENG EXAM
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Question 19Safety in the workshop should be a high priority in any engineering workshop. Which of the following lists common workshop safety actions in the correct order to minimise risk?
1st action 2nd action 3rd action 4th action 5th action
A. Identify tools. Identify risks. Use tools. Identify areas for improvement.
Document changes.
B. Use tools. Identify tools. Identify risks. Document changes.
Identify areas for improvement.
C. Document changes.
Identify risks. Use tools. Identify tools. Identify areas for improvement.
D. Identify tools. Identify areas for improvement.
Use tools. Document changes.
Identify risks.
Question 20The energy of water stored in a dam is to be used to generate electricity using a small turbine generator. Which of the following indicates the main energy transformations in the system as electricity is generated?A. electrical mechanical potentialB. kinetic mechanical electrical C. potential kinetic electricalD. kinetic electrical potential
2020SYSENGEXAM 10
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Question 1 (2marks)Figure1isablockdiagramofanautomatedandcontrolledsystem.
Figure 1
Usingthelistoftermsbelow,completetheblockdiagrambywritingtheappropriatetermineachoftheboxesprovided.
input feedback system output
SECTION B
Instructions for Section BAnswerall questionsinthespacesprovided.Allcalculationsmustshowappropriateformulasandworking.Whereananswerboxisprovided,writeyourfinalanswerinthebox.Ifananswerboxhasaunitprintedinit,giveyouranswerinthatunit.Unlessotherwiseindicated,thediagramsinthisbookarenotdrawntoscale.
11 2020SYSENGEXAM
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Question 2 (6marks)Anelectricmotor,M,isusedtopullaloadonaninclinedplane,asshowninFigure2.
M
T B
A
3 m
4 m
Figure 2
a. TherequiredmechanicalworktomovetheloadfrompointAtopointBis3000J.
Calculatetheforce,T,requiredbytheelectricmotortopulltheloadfrompointAtopointB. Showyourworking. 2marks
N
b. Theelectricalenergyusedbytheelectricmotortolifttheloadis3192J.
CalculatetheefficiencyofmovingtheloadfrompointAtopointB.Giveyouranswercorrecttothenearestwholenumber.Showyourworking. 2marks
%
c. Calculatethemassoftheloadusingg=10ms−2.Showyourworking.Usethefollowingformula. 2marks
force=mass×accelerationduetogravity
kg
2020 SYSENG EXAM 12
SECTION B – Question 3 – continued
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Question 3 (10 marks)Figure 3 shows a schematic diagram for an electric circuit. The voltage of the power supply is 30 VDC,andtheresistorsR1,R2andR3areall60Ω.Initiallytheswitch,S,isopen.
A1 A2
V30 VDC R1 = 60 Ω
R2 = 60 Ω S
R3 = 60 Ω
Figure 3
a. Calculatetheexpectedreadingsonthevoltmeter,V,andtheammeters,A1 and A2. Show your working. 4 marks
Voltmeter V V
Ammeter A1 A Ammeter A2 A
b. Afteraperiodofcorrectfunctioning,acomponentinthecircuitdevelopsafault.Duetothisfault,thereadingonvoltmeterVbecomes30VandthereadingonammeterA1 becomes 0 A.
Identify the faulty component. Give your reasoning. 3 marks
13 2020SYSENGEXAM
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c. Afterreplacingthefaultycomponent,theswitchisclosed.
WhatisthepowerdissipatedbyresistorR1withtheswitchclosed?Showyourworking. 3marks
W
2020SYSENGEXAM 14
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Question 4 (3marks)Inthetablebelow,drawtheelectric/electronicsymbolforeachofthecomponentslisted.
Component Electric/electronic symbol
battery
PNPtransistor
variableDCpowersupply
capacitor
light-emittingdiode(LED)
light-dependentresistor(LDR)
15 2020SYSENGEXAM
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Question 5 (4marks)Asolarenergystoragesystemprovidespowerforanightlight,asshowninFigure4.Thestoragesystemreliesonacapacitor,X,tostorecharge.
night lightX
solar panel
Figure 4
a. Describethetypeofcapacitorthatwouldbebestsuitedtothisapplication.Giveyourreasoning. 2marks
b. Whatisthepurposeoftheresistorconnectedinseriestothelightsource?Giveyourreasoning. 2marks
2020SYSENGEXAM 16
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Question 6(7marks)ThecoolingunitofasmallrefrigeratoriscontrolledbyathermistorusingthecircuitshowninFigure5.
12 VDC
thermistor
variableresistor
Voutput
Figure 5
a. Explainthefunctionofthevariableresistor. 2marks
b. OnFigure5,indicatewhereanammetershouldbelocatedtomeasurethecurrentflowingthroughthethermistor. 1mark
c. Ifthevariableresistorissetat1kΩandVoutput=4V,calculatethepowerconsumedbythevariableresistor.Showyourworking.Youmustincludetheunit. 4marks
17 2020SYSENGEXAM
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Question 7 (6marks)Benhasdesignedandbuiltascaledversionofarescuerobotforretrievinginjuredchildren.Hisprojectusesawinchsubsystemthatisconnectedtoa12VDC-poweredmotorviaachainandsprocketmechanism.ThisrescuerobotisshowninFigure6.
winch
motor
Figure 6
a. ExplainwhyBenshoulddesignandmodeltherescuerobot’ssubsystem. 2marks
b. ProposeoneappropriatediagnostictestthatBenshouldconsiderforthemotorisedchainandsprocketmechanism.Giveyourreasoning. 2marks
c. Evaluationisanimportantpartofthesystemsengineeringprocess.
i. WhyisitimportantforBentoevaluatehisrescuerobotsubsystem? 1mark
ii. WhenshouldBenevaluatehisrescuerobotsubsystem? 1mark
2020 SYSENG EXAM 18
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Question 8 (5 marks)Figure 7 shows a typical wind farm used to generate renewable energy.
Source:PremierofVictoria(website),‘Araratwindfarmpoweringahead’, mediarelease,27June2017;©StateofVictoria
Figure 7
a. What type of current would the wind turbines shown in Figure 7 typically produce? 1 mark
b. Identify twofeaturesofthewindturbinethatcouldbemodifiedtoimproveitsefficiency. 2 marks
c. Explain one way in which computer simulation software can assist engineers in the design of wind turbine blades. 2 marks
19 2020SYSENGEXAM
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Question 9 (3marks)Aroboticpoolcleanerhasapowerratingof2000Wandthemotorissuppliedfromthemainpowersupplyusingatransformer.Fourprocesses,includingoneunknownprocess,runbytheroboticpoolcleanerarelistedinthetablebelowwiththeirrespectivepowerconsumptions.
Robotic pool cleaner process Power consumption
motordrive 1000W
waterpump 650W
soundfromthemotorortransformer 45W
unknown 305W
a. Suggestonepossibleroboticpoolcleanerprocessfortheunknownprocesslistedinthetableabove. 1mark
b. Calculatetheoverallefficiencyoftheroboticpoolcleanersystemifthemotordriveandthewaterpumpareconsideredusefulprocesses.Showyourworking. 2marks
%
2020 SYSENG EXAM 20
SECTION B – Question 10 – continued
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Question 10 (6 marks)Figure 8 shows part of a simple steering system using a worm drive and levers to change the direction of the front wheels on a car.
drop arm
to steering rack
spur gear
to steering wheel housing
worm drive
Figure 8
a. State one advantage of using the worm drive as the initial input to the steering system. 1 mark
b. Ifthespurgearhadsevenworkingteeth,withonlyonetoothmeshingwiththewormdriveatanytime,whatisthegearboxratio? 1 mark
21 2020SYSENGEXAM
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c. ThesteeringmechanismshowninFigure9aissimplifiedintothelevershowninFigure9b.
100 mm
250 mm
point A
spur gear
worm drive
100 mm
250 mm
point A
pivot pointF = 200 N
Figure 9a Figure 9b
Whenthedriverofthecarturnsthesteeringwheel,theforceexertedonthespurgearis 200N,asshowninFigure9b.
CalculatetheforceatpointAonthesteeringarm.Showyourworking.Youmustincludetheunit. 4marks
2020SYSENGEXAM 22
SECTION B – Question 11 –continued
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Question 11 (5marks)Jemmahasdesignedasmallelectricmotor-drivencaraspartofaschoolprojecttoinvestigatedrivemechanisms.Shehasusedarubberbandbeltdrivesystemtoconnectthemotortothewheels,asshowninFigure10.
motor
rubber bandbelt drive
Figure 10
a. Whatisoneadvantageofusingarubberbandbeltdrivesystemforasmallelectric motor-drivencar? 1mark
23 2020SYSENGEXAM
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Aclose-upoftherubberbandbeltdrivesystemisshowninamodifiedset-upinFigure11.Thespeedofthewheelis40revolutionsperminute(rpm).
75 mm
wheel
motor Ø 5 mm
Figure 11
b. UsetheinformationgiveninFigure11toanswerthefollowingquestions.
i. Calculatetheexpectedspeedofthesmallelectricmotor-drivencarinmetresperminute.Showyourworking. 2marks
mmin–1
ii. Convertyouranswerfrompart b.i.tometrespersecond.Showyourworking. 1mark
ms–1
c. Jemmawouldlikethesmallelectricmotor-drivencartobeabletoreachahighermaximumspeed.
SuggestonechangeJemmacouldmaketohercartoachievethis. 1mark
2020SYSENGEXAM 24
SECTION B – Question 12 –continued
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Question 12 (7marks)Figure12showsacross-sectionalfrontviewofasewingmachine.Thesewingmachineusesabelttoconnectthemotortothedrivewheel,asshown.
drive wheel
belt
motor wheelmotor
drive shaft
crankshaft
needle bar
needle
A
Figure 12
a. Describetheroleoffrictionbetweenthebeltandthedrivewheel. 2marks
b. Themotorwheelhasadiameterof20mm.Thedrivewheelhasadiameterof180mm.
Calculatetherotationspeedofthemotorwheelforthedrivewheeltospinat150rpm.Showyourworking. 2marks
rpm
25 2020SYSENGEXAM
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c. Figure13showsacross-sectionalviewlookingfrompointAinFigure12directlyatthecrankshaft.
linear bearings
needle
drive shaft
crankshaft
needle bar
sewing foot
Figure 13
UsingtheadditionalinformationprovidedinFigure13,explainhowtherotationalmovementofthemotoristransformedintothereciprocatingmotionofthesewingneedle. 3marks
2020SYSENGEXAM 26
SECTION B – Question 13 –continued
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Question 13 (8marks)Charlieisdeliveringalargeheavyboxusingatiptruckwithatraythatcanbetiltedatanangle,asshowninFigure14.Whenunloadingthebox,heobservesthattheboxdoesnotstartmovinguntilthetrayistiltedatacertainangle,A.AsthetrayisraisedabovetheangleA,theboxslidesdownwards.
Ahydraulic ram
tray
pivot
box
Figure 14
a. Whatclassofleveristhetiptruck’stray? 1mark
b. AttheangleA,theboxstartstomove.
UsingNewton’slaws,explainwhythishappens. 3marks
27 2020SYSENGEXAM
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c. Thetiptruckusesahydraulicsystemtoraisethetray,asshowninFigure15.
Ø 50 mm
Ø 250 mm
hydraulic ram
6000 N
Figure 15
Toliftthetrayandthebox,thepistonmustexertaforceof6000Nontheundersideofthetray.
CalculatethepressureneededintheshadedareaofFigure15tocreatethe6000Nforcerequired.Showyourworking. 2marks
kPa
d. Figure16showsthehydraulicraminthefullyextendedposition.TworegionsoftherodarelabelledpointBandpointC.
hydraulic ramB
C
Figure 16
Fourtypesofstressaregivenbelow.
tension compression torsion shear
Fromtheoptionsgiven,selectthetypeofstressonpointBandonpointC,andwriteyouranswersintheboxesprovidedinFigure16. 2marks
2020SYSENGEXAM 28
END OF QUESTION AND ANSWER BOOK
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Question 14 (3marks)Input-process-output(IPO)diagramscanbeusedtobreakdownanysystemintosmallerpartsforanalysis.IPOdiagramsallowtheidentificationoftheinputsandoutputsofasystemandanyprocessesthattakeplace.
CompletetheIPOdiagraminFigure17foracordlessdrillmotorsystembywritingappropriatelabelsintheboxesprovided.
Figure 17
Question 15 (5marks)ThenumberofelectricvehiclesonAustralianroadsiscurrentlylowerthaninotherdevelopedcountries,butthenumberisexpectedtogrowascheapermodelsarriveandmorecharginginfrastructureisbuilt.
EvaluatethepotentialbenefitsandchallengesofusingelectricvehiclesinAustraliaintermsofeconomicandenvironmentalsustainability.
SYSTEMS ENGINEERING
Written examination
FORMULA SHEET
Instructions
Please remove from the centre of this book during reading time.This formula sheet is provided for your reference.
© VICTORIAN CURRICULUM AND ASSESSMENT AUTHORITY 2020
SYSENG EXAM 2
THIS pAGE IS bLANk
3 SYSENG EXAM
END OF FORMULA SHEET
Systems Engineering formulas
gear ratio final = gear ratio 1 × gear ratio 2 efficiency = output energyinput energy
× 100%
gear ratio = number of teeth on driven gearnumber of teeth on driver gear efficiencyTotal = efficiency1 × efficiency2
gear A rpmgear B rpm
number of teeth gear Bnumber of teeth
= gear A mechanical advantage load
effort=
pulley A rpmpulley B rpm
radius of pulley Bradius of pulle
=yy A force = pressure × area
voltage = current × resistance torque = force × distance
power = voltage × current frequency = 1period
area of circle = r2 ( = 3.14) speed = distancetime
circumference of circle = 2r
resistors in series Rt = R1 + R2 + R3 + … capacitors in series1
C= 1
C+ 1
C1
Ct 1 2 3+
…
resistors in parallel 1 1 1 1
2 3R R R Rt 1= + +
… capacitors in parallel Ct = C1 + C2 + C3 + …
two resistors in parallel R R RR Rt = +
×1 2
1 2
Colour codes
Colour Value Colour Value
black 0 blue 6
brown 1 violet 7
red 2 grey 8
orange 3 white 9
yellow 4 gold 5%
green 5 silver 10%
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