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WorkandEnergyReviewPartA:ForcedChoiceQuestions1.Whichofthefollowingstatementsaretrueaboutwork?Includeallthatapply.a. Workisaformofenergy.b. AWattisthestandardmetricunitofwork.c. UnitsofworkwouldbeequivalenttoaNewtontimesameter.d. Akgm2/s2wouldbeaunitofwork.e. Workisatimebasedquantity;itisdependentuponhowfastaforcedisplacesan

object.f. Supermanappliesaforceonatrucktopreventitfrommovingdownahill.Thisisan

exampleofworkbeingdone.g. Anupwardforceisappliedtoabucketasitiscarried20macrosstheyard.Thisisan

exampleofworkbeingdone.h. Aforceisappliedbyachaintoarollercoastercartocarryitupthehillofthefirst

dropoftheShockwaveride.Thisisanexampleofworkbeingdone.i. Theforceoffrictionactsuponasoftballplayerasshemakesaheadfirstdiveinto

thirdbase.Thisisanexampleofworkbeingdone.j. Aneraseristiedtoastring;apersonholdsthestringandappliesatensionforceas

theeraserismovedinacircleatconstantspeed.Thisisanexampleofworkbeingdone.

k. Aforceactsuponanobjecttopushtheobjectalongasurfaceatconstantspeed.Byitself,thisforcemustNOTbedoinganyworkupontheobject.

l. Aforceactsuponanobjectata90degreeangletothedirectionthatitismoving.Thisforceisdoingnegativeworkupontheobject.

m. AnindividualforcedoesNOTdopositiveworkuponanobjectiftheobjectismovingatconstantspeed.

n. Anobjectismovingtotheright.Aforceactsleftwarduponit.Thisforceisdoingnegativework.

o. Anonconservativeforceisdoingworkonanobject;itistheonlyforcedoingwork.Therefore,theobjectwilleithergainorlosemechanicalenergy.

2.Whichofthefollowingstatementsaretrueaboutpower?Includeallthatapply.a. Powerisatimebasedquantity.b. Powerreferstohowfastworkisdoneuponanobject.c. Powerfulpeopleorpowerfulmachinesaresimplypeopleormachineswhichalways

doalotofwork.d. Aforceisexertedonanobjecttomoveitataconstantspeed.Thepowerdelivered

bythisforceisthemagnitudeoftheforcemultipliedbythespeedoftheobject.e. ThestandardmetricunitofpoweristheWatt.f. IfpersonAandpersonBdothesamejobbutpersonBdoesitfaster,thenpersonA

doesmoreworkbutpersonBhasmorepower.

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g. TheNewtonmeterisaunitofpower.h. A60kgboyrunsupa2.0meterstaircasein1.5seconds.Hispowerisapproximately

80Watt.i. A300Newtonforceisappliedtoaskiertodragherupaskihillataconstantspeed

of1.5m/s.Thepowerdeliveredbythetoeropeis450Watts.3.Considerthefollowingphysicalsituations.Foreachcase,determinetheanglebetweentheindicatedforce(inboldfacetype)andthedisplacement("theta"intheworkequation).

a.0degrees b.180degrees c.90degrees d.30degrees e.60degreesa. Arightwardappliedforceisusedtodisplaceatelevisionsettotheright.b. Theforceoffrictionactsuponarightwardmovingcartobringittoastop.c. Awaiterusesanappliedforcetobalancetheweightofatrayofplatesashecarries

thetrayacrosstheroom.d. Theforceofairresistanceactsuponaverticallyfallingskydiver.e. Theforceoffrictionactsuponabaseballplayerasheslidesintothirdbase.f. AnappliedforceisusedbyafreshmantoliftaWorldCivilizationbooktothetop

shelfofhislocker.g. Abucketofwateristiedtoastringandtensionsuppliesthecentripetalforceto

keepitmovinginacircleatconstantspeed.h. Anappliedforceactingat30degreestothehorizontalisusedtodisplaceanobject

totheright.i. Agroupoffootballplayersuseanappliedforcetopushasledacrossthegrass.j. Thetensionintheelevatorcablecausestheelevatortoriseataconstantspeed.k. Inaphysicslab,anappliedforceisexertedparalleltoaplaneinclinedat30degrees

inordertodisplaceacartuptheincline.l. Anappliedforceisexertedupwardsandrightwardsatanangleof30degreestothe

verticalinordertodisplaceanobjecttotheright.m. Achildrestsontheseatofaswingwhichissupportedbythetensioninitscables;he

swingsfromthehighestpositiontoitslowestposition.4.Considerthefollowingphysicalsituations.Identifywhethertheindicatedforce(inboldfacetype)doespositivework,negativeworkornowork.

a.PositiveWork b. Negative Work c. No WorkDescriptionofPhysicalSituation

+,,ornoWorka.Acableisattached toabucketand the force of tension is usedtopullthebucketoutofawell. _______________b.RustyNalesusesahammertoexert an applied force upon astubbornnailtodriveitintothewall. _______________

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c.NeartheendoftheShockwave ride, a braking system exerts anappliedforceuponthecoastercartobringittoastop. _______________d.Theforceoffrictionactsupona baseball player as he slidesintothirdbase. _______________e.Abusyspiderhangsmotionless from a silk thread, supported bythetensioninthethread. _______________f.Inbaseball,thecatcherexertsan abrupt applied force upon theballtostopitinthecatcher'smitt. _______________g.Inaphysicslab,anappliedforce is exerted parallel to a planeinclinedat30degreesinordertodisplaceacartuptheincline. _______________h.Apendulumbobswingsfromits highest position to its lowestpositionundertheinfluenceoftheforceofgravity. _______________5.Whichofthefollowingstatementsaretrueaboutconservativeandnonconservativeforces?Includeallthatapply.a. Aforceisregardedasaconservativeforceifitdoesworkbutdoesnotremove

mechanicalenergyfromasystemofobjects.b. Aforceisregardedasanonconservativeforceifitdoesnotaddmechanicalenergy

toasystemofobjects.c. Theforceofgravityandelastic(spring)forcearebothexamplesofaconservative

forces.d. Appliedforces,airresistance,frictionforces,andtensionarecommonexamplesof

nonconservativeforces.e. Physicistsenvybiologists'abilitytoinstillorderontheworldofanimalspecies

throughtheirtaxonomicsystem.Sophysicistshavemadeahabitofidentifyingforcesasconservativeandnonconservativeforcesinordertoinstillorderontheworldofforces.

f. Ifanonconservativeforceactsuponanobject,thentheobjectwilleithergainorlosemechanicalenergy.

g. Iftheonlyforceswhichdoworkuponanobjectareconservativeforces,thentheobjectwillconserveitsmechanicalenergy.

h. Ifthesumofanobject'sKEandPEisremainingconstant,thennonconservativeforcesareNOTdoingwork.

i. IfworkisNOTdoneonanobjectbyanonconservativeforce,thentheobjectwillexperienceatransformationofenergyfromkinetictopotentialenergy(orviceversa).

j. Anobjectstartsfromanelevatedpositionwith50Jofpotentialenergyandbeginsitsfalltowardstheground.IfnonconservativeforcescanbeassumedtoNOTdowork,thenatsomepointduringthefalltheobjectwillhave20Jofpotentialenergyand30Jofkineticenergy.

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6.Whichofthefollowingstatementsaretrueaboutkineticenergy?Includeallthatapply.a. Kineticenergyistheformofmechanicalenergywhichdependsuponthepositionof

anobject.b. Ifanobjectisatrest,thenitdoesnothaveanykineticenergy.c. Ifanobjectisontheground,thenitdoesnothaveanykineticenergy.d. Thekineticenergyofanobjectisdependentupontheweightandthespeedofan

object.e. Fastermovingobjectsalwayshaveagreaterkineticenergy.f. Moremassiveobjectsalwayshaveagreaterkineticenergy.g. Kineticenergyisascalarquantity.h. Anobjecthasakineticenergyof40J.Ifitsmassweretwiceasmuch,thenitskinetic

energywouldbe80J.i. Anobjecthasakineticenergyof40J.Ifitsspeedweretwiceasmuch,thenits

kineticenergywouldbe80J.j. ObjectAhasamassof1kgandaspeedof2m/s.ObjectBhasamassof2kganda

speedof1m/s.ObjectsAandBhavethesamekineticenergy.k. Anobjectcanneverhaveanegativekineticenergy.l. Afallingobjectalwaysgainskineticenergyasitfalls.m. A1kgobjectisacceleratedfromresttoaspeedof2.0m/s.Thisobjectgains4.0

Joulesofkineticenergy.n. Ifworkisdoneonanobjectbyanonconservativeforce,thentheobjectwilleither

gainorlosekineticenergy.7.Whichofthefollowingstatementsaretrueaboutpotentialenergy?Includeallthatapply.a. Movingobjectscannothavepotentialenergy.b. Potentialenergyistheenergystoredinanobjectduetoitsposition.c. Bothgravitationalandelasticpotentialenergyaredependentuponthemassofan

object.d. Thegravitationalpotentialenergyofanobjectisdependentuponthemassofthe

object.e. Ifthemassofanelevatedobjectisdoubled,thenitsgravitationalpotentialenergy

willbedoubledaswell.f. Gravitationalpotentialenergyislostasobjectsfreefalltotheground.g. Thehigherthatanobjectis,themorepotentialenergywhichitwillhave.h. TheunitofmeasurementforpotentialenergyistheJoule.i. A1kgmassataheightof1meterhasapotentialenergyof1Joule.j. A1kgobjectfallsfromaheightof10mtoaheightof6m.Thefinalpotentialenergy

oftheobjectisapproximately40J.k. Ifworkisdoneonanobjectbyanonconservativeforce,thentheobjectwilleither

gainorlosepotentialenergy.

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8.Whichofthefollowingstatementsaretrueaboutmechanicalenergy?Includeallthatapply.a. Thetotalamountofmechanicalenergyofanobjectisthesumofitspotential

energyandthekineticenergy.b. Heatisaformofmechanicalenergy.c. Themechanicalenergyofanobjectisalwaysconserved.d. Whennonconservativeforcesdowork,energyistransformedfromkineticto

potential(orviceversa),butthetotalmechanicalenergyisconserved.e. Abowlingballismountedfromaceilingbywayofastrongcable.Itisdrawnback

andreleased,allowedtoswingasapendulum.Asitswingsfromitshighestpositiontoitslowestposition,thetotalmechanicalenergyismostlyconserved.

f. Whenafrictionforcedoesworkonanobject,thetotalmechanicalenergyofthatobjectischanged.

g. Thetotalmechanicalenergyofanobjectremainsconstantiftheonlyforcesdoingworkontheobjectareconservativeforces.

h. Ifanobjectgainsmechanicalenergy,thenonecanbecertainthatanonconservativeforceisdoingwork.

9.Rankthesefourobjectsinincreasingorderofkineticenergy,beginningwiththesmallest.

ObjectA Object B Object C Object Dm=5.0kgv=4.0m/sh=2.0m

m=10.0 kgv=2.0m/sh=3.00m

m = 1.0 kgv=5.0m/sh=5.0m

m=5.0 kgv=2.0m/sh=4.0m

10.Rankthesefourobjectsinincreasingorderofpotentialenergy,beginningwiththesmallest.

ObjectA Object B Object C Object Dm=5.0kgv=4.0m/sh=2.0m

m=10.0 kgv=2.0m/sh=3.00m

m = 1.0 kgv=5.0m/sh=5.0m

m=5.0 kgv=2.0m/sh=4.0m

NOTE:Thenext15questionsapproximatethevalueofgas10m/s/s.11.A1200kgcaranda2400kgcarareliftedtothesameheightataconstantspeedinaautoservicestation.Liftingthemoremassivecarrequires____work.a.less b.the same c.twiceasmuchd.fourtimesasmuch e.more than 4 times as much 12.Anarrowisdrawnbacksothat50Joulesofpotentialenergyisstoredinthestretchedbowandstring.Whenreleased,thearrowwillhaveakineticenergyof____Joules.

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a.50 b.morethan50 c. less than 5013.Achildliftsaboxupfromthefloor.Thechildthencarriestheboxwithconstantspeedtotheothersideoftheroomandputstheboxdown.Howmuchworkdoeshedoontheboxwhilewalkingacrosstheflooratconstantspeed?a.zeroJ b.more than zero Jc.moreinformationneededtodetermine14.A1000kgcarismovingat40.0km/hrwhenthedriverslamsonthebrakesandskidstoastop(withlockedbrakes)overadistanceof20.0meters.Howfarwillthecarskidwithlockedbrakesifitistravelingat120.km/hr?a.20.0m b.60.0m c. 90.0 m d. 120. m e.180.m15.Aplatformdiverweighs500N.Shestepsoffadivingboardthatiselevatedtoaheightof10metersabovethewater.Thediverwillpossess___Joulesofkineticenergywhenshehitsthewater.a.10 b.500 c.510 d. 5000 e. more than 5000.16.Aballisprojectedintotheairwith100Jofkineticenergy.Thekineticenergyistransformedintogravitationalpotentialenergyonthepathtowardsthepeakofitstrajectory.Whentheballreturnstoitsoriginalheight,itskineticenergyis____Joules.Doconsidertheeffectsofairresistancea.lessthan100 b. 100 c. more than 100d.notenoughinformationgiven17.Duringaconstructionproject,a2500Nobjectisliftedhighabovetheground.Itisreleasedandfalls10.0metersanddrivesapost0.100mintotheground.Theaverageimpactforceontheobjectis____Newtons.a.2500 b.25000 c. 250,000 d. 2,500,00018.A10Newtonobjectmovestotheleftat1m/s.Itskineticenergyisapproximately____Joules.a.0.5 b.1 c.10 d. more than 1019.LukeAutbeloestandsontheedgeofaroofthrowsaballdownward.Itstrikesthegroundwith100Jofkineticenergy.Lukenowthrowsanotheridenticalballupwardwiththesameinitialspeed,andthistoofallstotheground.Neglectingairresistance,thesecondballhitsthegroundwithakineticenergyof____J.a.lessthan100 b.100 c. 200 d. more than 200 e. noneofthese20.Anobjectatrestmayhave__________.

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a.speed b.velocity c.acceleration d. energy e.allofthese21.A50kgplatformdiverhitsthewaterbelowwithakineticenergyof5000Joules.Theheight(relativetothewater)fromwhichthediverdovewasapproximately____meters.a.5 b.10 c. 50 d. 10022.Ajobisdoneslowly,andanidenticaljobisdonequickly.Bothjobsrequirethesameamountof____,butdifferentamountsof____.Pickthetwowordswhichfillintheblanksintheirrespectiveorder.a.energy,work b.power, work c. work, energy d.work,powere.power,energy f.force,work g. power, force h.noneofthese23.Whichrequiresmorework:liftinga50.0kgcrateaverticaldistanceof2.0metersorliftinga25.0kgcrateaverticaldistanceof4.0meters?a.liftingthe50kgsack b. lifting the25kgsackc.bothrequirethesameamount of work 24.A50.0kgcrateisliftedtoaheightof2.0metersinthesametimeasa25.0kgcrateisliftedtoaheightof4meters.Therateatwhichenergyisused(i.e.,power)inraisingthe50.0kgcrateis____astherateatwhichenergyisusedtoliftthe25.0kgcrate.a.twiceasmuch b. half as much c. thesame25.Using1000.Jofwork,asmallobjectisliftedfromthegroundfloortothethirdfloorofatallbuildingin20.0seconds.Whatpowerwasrequiredinthistask?a.20W b.50W c.100 W d. 1000 W e.20000WPartB:StraightforwardComputationalProblems26.Approximatetheworkrequiredlifta2.5kgobjecttoaheightof6.0meters.27.Astudentappliesaforcetoacarttopullitupaninclinedplaneatconstantspeedduringaphysicslab.Aforceof20.8Nisappliedparalleltotheinclinetolifta3.00kgloadedcarttoaheightof0.450malonganinclinewhichis0.636mlong.Determinetheworkdoneuponthecartandthesubsequentpotentialenergychangeofthecart.28.Eddy,whosemassis65kg,climbsupthe1.6meterhighstairsin1.2s.ApproximateEddy'spowerrating.29.A51.7kghikerascendsa43.2meterhighhillataconstantspeedof1.20m/s.Ifittakes384stoclimbthehill,thendeterminea. kineticenergychangeofthehiker.b. thepotentialenergychangeofthehiker.

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c. theworkdoneuponthehiker.d. thepowerdeliveredbythehiker.30.An878kgcarskidstoastopacrossahorizontalsurfaceoveradistanceof45.2m.Theaverageforceactinguponthecaris7160N.Determine....a. theworkdoneuponthecar.b. theinitialkineticenergyofthecar.c. theaccelerationofthecar.d. theinitialvelocityofthecar.31.A510kgrollercoastercarstartsataheightof32.0m.Assumingnegligibleenergylossestofrictionandairresistance,determinethePE,KE,andspeedofthecaratthevariouslocations(A,B,C,D,andE)alongthetrack.

Location Height(m) PE (J) KE (J) velocity(m/s)Start 32.0 ________ ________ 0A 28.0 ________ ________ ________B 11.0 ________ ________ ________C 20.0 ________ ________ ________D 5.0 ________ ________ ________E 15.0 ________ ________ ________F 0 ________ ________ ________

32.A65.8kgskieracceleratesdownanicyhillfromanoriginalheightof521meters.Usetheworkenergytheoremtodeterminethespeedatthebottomofthehillif...a....noenergyislostorgainedduetofriction,airresistanceandothernonconservativeforces.b....1.40*105Jofenergyarelostduetoexternalforces.33.Usetheworkenergytheoremtodeterminetheforcerequiredtostopa988kgcarmovingataspeedof21.2m/sifthereisadistanceof45.7minwhichtostopit.PartC:WorkEnergyBarCharts,Analysis,andConceptualReasoning34.Considerthefollowingphysicalsituations.Identifytheforceswhichdoworkupontheindicatedobject(inboldfacetype)andcategorizethemasconservativeornonconservativeforces.Thenindicatewhetherthetotalmechanicalenergyoftheobjectchanges;ifitchanges,thenindicatewhetherthechangeisapositiveornegativechange.Finally,indicatewhetherthepotentialenergyandthekineticenergychanges;ifPEorKEchanges,thenindicatewhetherthechangeisapositiveornegativechange.

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DescriptionofPhysicalSituation

Identity of ForcesWhichDoWork: ChangeinTME ChangeinPE ChangeinKE

Conserv.Non

Conserv.Yes

(+or) NoYes

(+or) NoYes

(+or) Noa.Aforceisappliedtomoveaphysicscartfromthefloortothetopofaninclinedplaneataconstantspeed.

__________________ _____ _____ _____ _____ _____ _____

b.Aphysicsstudentscurriesupaflightofstairsatconstantspeed. __________________ _____ _____ _____ _____ _____ _____

c.Inamomentofunsupervisedphun,aphysicsstudenthoistsherselfontoastaircasebanisterandacceleratesdownthebanister.Ignoreallfrictionforces.

__________________ _____ _____ _____ _____ _____ _____

d.Aballisdroppedfromrestfromonthetopofahillandfallstothegroundbelow.Ignoreairresistance.

__________________ _____ _____ _____ _____ _____ _____

e.Aballleavestopofahillwithalargehorizontalvelocity.Itfallstothegroundbelow.Ignoreairresistance.

__________________ _____ _____ _____ _____ _____ _____

f.AHotWheelscarisatrestatanelevatedpositionalonganinclinedplane;itisreleasedandrollstoapositionalongtheground.Ignoreairresistance.

__________________ _____ _____ _____ _____ _____ _____

g.AHotWheelscarisinmotionatthebottomofahillwhenithitsa

__________________ _____ _____ _____ _____ _____ _____

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computerdisketteboxandskidstoastop.h.Apendulumbobswingsfromitshighestpositiontoitslowestposition. __________________ _____ _____ _____ _____ _____ _____

i.Aphysicscartisreleasedfromrestatanelevatedpositionalonganinclinedplane;itisreleasedandrollstoapositionalongtheinclineapproximately5cmfromthebottom.

__________________ _____ _____ _____ _____ _____ _____

35.Thediagramsbelowdepictaphysicalsituation.Analyzeeachsituationandconstructworkenergybarcharts.DescriptionofPhysicalSituation WorkEnergyBarCharta.AHotWheelscarstartsfromrestontopofaninclinedplaneandrollsdowntheinclinethroughaloopandalongahorizontalsurface.Ignoretheeffectoffrictionandairresistanceonthecar. b.AHotWheelscarstartsfromrestontopofaninclinedplaneandrollsdowntheinclinethroughaloopandalongahorizontalsurface.Frictionandairresistancehaveasignificanteffectonthecar.

c.Apendulumbobismountedontopofalabpoleanddrawnbacktoastringwhichittiedbetweentwootherpoles.Thependulumbobisreleasedfromrest.Uponreachingthevertical,thestringhitsabarrierandanewpivotpointisestablishedasthe

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bobcontinuesinmotionalongan upwardtrajectory.Ignoretheeffectofairresistance.d.Atrackisconstructedbystretchingagroovedandpliablematerialbetweentwolabpoles.AmetalballstartsfromrestatpointAandrollsalongthegroovetopointB.Frictionandairresistancehaveaneffectupontheball'smotion.

e.Adartisplacedinadartgunandthespringsarecompressed.Thetriggerispulledandthedartisprojectedtowardsawall.Thedartcollideswiththewallandstickstoit.Ignoretheeffectoffrictionandairresistance.

f.BenLaborinappliesaforcetopushacratefromthebottomofaninclinedplanetothetopataconstantspeed.

36.Severalphysicalsituationsaredescribedbelow.Foreachsituation,simplifytheworkenergyequationbycancelinganyzerotermsandanyenergyterms(whetherKEorPE)whichareunchanging.Explaineachtermwhichgetscanceled.Thefirstproblemisdoneasanexample.DescriptionofPhysicalSituation Simplification ofWorkEnergy

Equationa.Aballstartsfromrestontopofatallpillarandfallstothegroundbelow.Assumetheeffectofairresistanceisnegligible.

KEi+PEi+Wnc=KEf+PEf

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b.Aballstartsfromrestatanelevatedpositionalonganinclinedplaneandrollstothegroundbelow.Assumethattheeffectoffrictionandairresistanceisnegligible.

KEi+PEi+Wnc=KEf+PEf

c.Aballstartsfromrestatanelevatedpositionalonganinclinedplaneandrollstothegroundbelow.Considertheeffectoffrictionandairresistance.

KEi+PEi+Wnc=KEf+PEf

d.Atrackisconstructedbystretchingagroovedandpliablematerialbetweentwolabpoles.AmetalballstartsfromrestatpointAandrollstopointB.Frictionandairresistancehaveaneffectupontheball'smotion.

KEi+PEi+Wnc=KEf+PEf

e.Apendulumbobismountedontopofalabpoleanddrawnbacktoastringwhichittiedbetweentwootherpoles.Thependulumbobisreleasedfromrest.Uponreachingthevertical,thestringhitsabarrierandanewpivotpointisestablishedasthebobcontinuesinmotionalonganupwardtrajectory.Ignoretheeffectofairresistance.

KEi+PEi+Wnc=KEf+PEf

f.AHotWheelscarstartsfromrestontopofaninclinedplaneandrollsdowntheinclinethroughaloopand

KEi+PEi+Wnc=KEf+PEf

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alongahorizontalsurface.Friction and airresistancehaveasignificanteffectonthecar.g.Anunattendedhotdogwagonstartsfromrestandrollsdownahillandupasecondhill.Ignoretheeffectoffrictionandairresistance.

KEi+PEi+Wnc=KEf+PEf

h.Arollercoastercarisalreadyinmotiononthetopofthefirstdropandrollsalongthetrackoveracoupleofhills.Ignoretheeffectoffrictionandairresistance.

KEi+PEi+Wnc=KEf+PEf

i.Acrosscountryskierisinmotionontopofasmallhill.Heskisdownthehillintothevalleyandupasecondsmallerhill.Heuseshispolestopropelhimselfduringtheentiremotion.Ignoretheeffectoffrictionandairresistance.

KEi+PEi+Wnc=KEf+PEf

PartD:ComplexAnalysisandProblemSolving37.A21.3kgchildpositionshimselfonaninnertubewhichissuspendedbya7.28mlongropeattachedtoastrongtreelimb.Thechildandtubeisdrawnbackuntilitmakesa17.4degreeanglewiththevertical.Thechildisreleasedandallowedtoswingtoandfrom.Assumingnegligiblefriction,determinethechild'sspeedathislowestpointinthetrajectory.38.Abaseballplayercatchesa163grambaseballwhichismovinghorizontallyataspeedof39.8m/s.Determinetheforcewhichshemustapplytothebaseballifhermittrecoilsahorizontaldistanceof25.1cm.39.A62.9kgdownhillskierismovingwithaspeedof12.9m/sashestartshisdescentfromalevelplateauat123mheighttothegroundbelow.Theslopehasanangleof14.1degreesandacoefficientoffrictionof0.121.Theskiercoaststheentiredescentwithoutusinghispoles;uponreachingthebottomhecontinuestocoasttoastop;thecoefficientoffrictionalongthelevelsurfaceis0.623.Howfarwillhecoastalongthelevelareaatthebottomoftheslope?40.A29.1kgsledderistravelingalongalevelareawithaspeedof8.96m/swhensheapproachesagentleinclinewhichmakesanangleof12.5degreeswiththehorizontal.

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Ifthecoefficientoffrictionbetweenthesledandtheinclineis0.109,thenwhatwillbeherspeedatthebottomoftheinclinedplane,located8.21mabovethetopoftheincline.41.A221gramballisthrownatanangleof17.9degreesandaspeedof36.7m/sfromthetopofa39.8mhighcliff.Determinetheimpactspeedoftheballwhenitstrikestheground.Assumenegligibleairresistance.42.ClairedeAisleshasjustcompletedhershoppingatthegroceryfoodstore.Sheaccidentallybumpsher42.5kgcart,settingitinmotionfromrestdownahillinclinedat14.9degrees.Upondescendingadistanceof9.27metersalongtheinclinedplane,thecarthitsatreestump(whichwasplacedintheparkinglotforthesolepurposeofthisproblem).A0.295kgcanoftomatosoupisimmediatelyhurledfromthemovingcartandheadstowardsWillN.Tasue'sbrandnewLexus.UponstrikingtheLexus,thetomatosoupcancreatesadentwithadepthof3.16cm.NoahFormula,whoiswatchingtheentireincidentandfixingtodosomephysics,attemptstocalculatetheaverageforcewhichtheLexusappliestothesoupcan.AssumenegligibleairresistanceandfrictionforcesandhelpNoahout.43.PeteZariaappliesa11.9Newtonforcetoa1.49kgmugofrootbeerinordertoaccelerateitfromrestoveradistanceof1.42m.Oncereleased,howfarwillthemugslidealongthecountertopifthecoefficientoffrictionis0.728?44.SuzieLovtaskihasamassof49.7kg.Sheisatrestontopofahillwithaheightof92.6mandaninclineangleof19.2degrees.Shecoastsdownthehilltothebottomandeventuallycomestoastop;sheneverusesherpolestoapplyaforce.Thecoefficientoffrictionis0.0873alongthehilland0.527alongthehorizontalsurfaceatthebottom.WhattotaldistancewillSuziecoast(includebothinclineandlevelsurface)?45.MiaKneezhirtjumpsfromasecondstorydormroom(h=7.91m)tothegroundbelow.Uponcontactwiththeground,sheallowsher62.4kgbodytocometoanabruptstopashercenterofgravityisdisplaceddownwardsadistanceof89.2cm.CalculatetheaverageupwardforceexertedbythegrounduponMia'sfragilebody.