(2a) 2021 BBSS O PRELIM Sec 4E Pure Physics (6091) P2

Name:……………………………………….( ) Class:……………. BukitBatokSecondarySchoolGCE‘O’ LEVELPRELIMINARYEXAMINATIONS2021SECONDARYFOUREXPRESS PHYSICSPaper2Theory 6091/ 0227Aug20210800−0945h1hour 45minutesCandidatesanswerontheQuestionPaperNoAdditionalMaterialsarerequired.______________________________________________________________________________________ READTHESEINSTRUCTIONSFIRST Writeyourname,class,andclassregisternumberonalltheworkyouhandin.Writeindarkblueorblackink.YoumayuseanHBpencilforanydiagramsorgraphs.Donotusestaples,paperclips,glueorcorrectionfluid. SectionAAnswer allquestionsinthespaceprovided. SectionBAnswer allquestionsinthespaceprovided.Question12hasachoiceofpartstoanswer. Candidatesareremindedthat allquantitativeanswersshouldincludeappropriateunits.Theuseofanapprovedscientificcalculatorisexpected,whereappropriate.Candidatesareadvisedtoshowalltheirworkinginaclearandorderlymanner,asmoremarksareawardedforsounduseofPhysicsthanforcorrectanswers. Attheendofexamination,fastenallyourworksecurelytogether.Thenumberofmarksisgiveninbrackets[]attheendofeachquestionorpartquestion. FOREXAMINER’SUSESectionASectionBTOTAL

BBSS/2021/OPrelim/Sec4E/Physics(6091)/P2 ThisQuestionPaperconsistsof 21printedpages. Applyingpast knowledgetonewsituations 2

BBSS/2021/OPrelim/Sec4E/Physics(6091)/P2 SectionAAnswer allthequestionsinthissection.1 Amanstandsattheedgeofaverticalcliffandheprojectsastoneverticallyupwards.Thestonereacheditsgreatestheight,fellpastthemanandhitthebottomofthecliff. Themotionofthestoneisrepresentedbythevelocity-timegraphshowninFig.1.1. Fig. 1.1(a) ExplainhowFig.1.1showsthatairresistancehasnegligibleeffectonthemotionofthestone.……………………………………………………………………………………………... [1] (b) BasedonthedatashowninFig.1.1,determine(i) thegreatestheightachievedbythestone, greatestheight=…………………….Questioncontinuesonnext page… [2] Applyingpast knowledgetonewsituations 3

BBSS/2021/OPrelim/Sec4E/Physics(6091)/P2 (ii) theheightofthecliff. heightofcliff=……………………. [2] 2 Fig.2.1showsanapparatusthatdemonstrateshowacoinandapieceofpaperfallfromrestthroughair. Fig. 2.1 (a) Statetheinitialaccelerationofthepaperasitfallsfromrest. ……………………………………………………………………………………………... [1] (b) ThecoinandpaperareatthepositionsshowninFig.2.1.Byconsideringtheforcesactingoneachobject,explainwhy(i) thepaperfallswithconstantvelocity, ……………………………………………………………………………………… ……………………………………………………………………………………… [1] (ii) thecoinstillaccelerates. ……………………………………………………………………………………… ……………………………………………………………………………………… ……………………………………………………………………………………… [2] Applyingpast knowledgetonewsituations 4

BBSS/2021/OPrelim/Sec4E/Physics(6091)/P2 3 Fig.3.1showsasphereofweight6.5NsuspendedbyawirefrompointX.ThesphereispulledtoonesidebyahorizontalforceFsothatthewiremakesanangleof30°withthevertical. Fig. 3.1 Useascaleof1.0cmtorepresent0.50N,drawascalediagraminthespacebelowtodeterminethemagnitudeof(a) thetension(TW )inthewire,(b) thehorizontalforceF. magnitudeofTW =…………………….magnitudeofF=……………………. [3] Applyingpast knowledgetonewsituations 5

BBSS/2021/OPrelim/Sec4E/Physics(6091)/P2 4 TheQinghai-TibetRailwayisahigh-altituderailwaythatstartsatXining(inQinghaiProvince)andendsatLhasa(inTibetAutonomousRegion)inChina.FromXiningtoLhasa,thelengthoftherailwayis1956kmandthetriptakes21hoursonaverage. Fig.4.1showshowthealtitude(abovesealevelinmetres)varyasatraintravelsfromBeijingtoLhasa.ThetrainjourneyfromBeijingtoLhasawilltakemorethanaday. (a) DeterminetheaveragespeedofatraininmetrespersecondasittravelsfromXiningtoLhasa. averagespeed=………………………… [3] (b) Suggest onereasonwhytheaveragevelocityofthetrainisdifferentfromthevaluecalculatedinpart (a)above. [1]Applyingpast knowledgetonewsituations 6

BBSS/2021/OPrelim/Sec4E/Physics(6091)/P2 ……………………………………………………………………………………………...Questioncontinuesonnext page…(c) AmercurybarometerisbroughtfromBeijingtoLhasa.(i) Determinethegreatestchangeinaltitudeduringthejourney. greatestchangeinaltitude=………………………… [1] (ii) Hence,determinethegreatestchangeintheheightofthemercurycolumninthebarometerduringthejourney.(densityofair=1.29kg/m 3 ;densityofmercury=13600kg/m 3 ) greatestchangeinheightofmercurycolumn=………………………… [2] (d) Suggest onereasonwhythevaluecalculatedinpart (c)abovemaybeinaccurate. ……………………………………………………………………………………………... [1] Applyingpast knowledgetonewsituations 7

BBSS/2021/OPrelim/Sec4E/Physics(6091)/P2 5 Fig. 5.1 shows a uniformplankACof length3.0mandweight 100Nheldatequilibriumhorizontally.EndAoftheplankisfixed.Aboxofweight400NhangsatendCoftheplank.ThereisaropetiedatendBoftheplank.DistanceBCis1.0m. Fig. 5.1 (a) DeterminethemomentduetotheweightoftheplankaboutendA. moment=………………………… [2] (b) DeterminethetensionToftherope. tensionT=………………………… [2] Applyingpast knowledgetonewsituations 8

BBSS/2021/OPrelim/Sec4E/Physics(6091)/P2 Questioncontinuesonnext page…(c) WiththeplankstillpivotedatendAandtheboxisstillhangingatendCoftheplank,theropeexertsanupwardforceontheplank.Atoneinstant,theplankisheldatrestatthepositionshowninFig.5.2. Fig. 5.2 Atthisinstant,isthemagnitudeoftensionToftheropegreater,smallerorthesameasthevalueofTcalculatedinpart (b)above?Explainyouranswer. ……………………………………………………………………………………………... ……………………………………………………………………………………………... ……………………………………………………………………………………………... [2] 6 (a) Definewhatismeantby(i) workdone,and ……………………………………………………………………………………… ……………………………………………………………………………………… [1] (ii) power ……………………………………………………………………………………… [1] (b) Statetheprincipleofconservationofenergy ……………………………………………………………………………………………... ……………………………………………………………………………………………... ……………………………………………………………………………………………... [2] Applyingpast knowledgetonewsituations 9

BBSS/2021/OPrelim/Sec4E/Physics(6091)/P2 Questioncontinuesonnext page…(c) Fig.6.1showsarollercoasterofweight5000Nandinitiallyatrestataheightof15.0mabovetheground.Itisthenreleasedfromrestanditrollsalongthetrackfor50.0mbeforeitcomestoamomentaryrestatpointXwhichis11.0mabovetheground.Thetrackfeelswarmaftertherollercoasterrolledpastit. Fig. 6.1(i) Ignoring loss of energy to the surroundings through other means,determinetheworkdoneagainst frictionasit rollsfromitsinitial restpositiontopointX. workdoneagainstfriction=………………………… [2] (ii) Determine thefrictional force(assumedconstant throughout) that actsbetweentherollercoasterandthetrack. frictionalforce=………………………… [2] (iii) Amotor(notshowninFig.6.1)wasusedtoraisetherollercoasterfromgroundleveltoitsinitialrestposition15mabovegroundlevel.Giventhatthemotortakes30stodoso,whatisthepowerdissipatedbythemotor?(Ignoreenergylosttothesurroundingsasheatorsound). Applyingpast knowledgetonewsituations 10