中國(guó)大學(xué)mooc《College Physics II(Dalian University of Technology)1458633460 》章節(jié)測(cè)試答案

titleCollegePhysicsII(DalianUniversityofTechnology)1458633460中國(guó)大學(xué)mooc答案100分最新版content01PeriodicMotionUnitTest11、Amassof0.20kg,hungfromaspringwithaspringconstantof80.0N/m

,issetintoanup-and-downsimpleharmonicmotion.Ifthemassisdisplacedfromequilibriumby0.10mandreleasedfromrest,whatisitsspeedwhenmovingthroughtheequilibriumpoint?答案:2.0m/s2、TheFig.

isthe

v

(t

)curveforanobjectundergoingSHM.Whichofthefollowingistheoscillatingfunctionx

(t

)fortheobject?答案:3、Amassmattachedtoaverticalspring(withspringconstantk)isreleasedfromrestfromtherelaxedpositionofthespring.Whatistheamplitudeoftheresultingoscillation?答案:4、Amasshangingonaspringoscillatesvertically.IftheequilibriumpointoftheoscillationisadistancedbelowtherelaxedlengthofthespringandiftheamplitudeoftheoscillationisA.Whichisthemaximumkineticenergyoftheoscillation?

答案:5、Asimplependulumconsistsofamassivebobconnectedtotheendofaverylightstring.Ignoreairresistance.Whichoneofthefollowingchangesshouldbemadeinordertoincreasetheperiodofthependulum?答案:Increasethelengthofthestring.6、Ablockisattachedtoaspringhungvertically.Afterbeingslowlylowered,itishungatrestwiththespringstretchedby15.0cm.Iftheblockisraisedbackupandreleasedfromrestwiththespringunstretched,whatistheamplitudeofitsoscillations?答案:15.0cm7、Adampedharmonicoscillatorwiththenaturalangularfrequency

andverylittledampingisdrivenbyanexternalforce

.Whenitreachesthestablestate,theoscillatingangularfrequencyis______答案:8、ThegraphofvibrationoftheparticleinSHMisshowninthefigure.Theperiod

ofthevibrationequals___

s.

答案:(以下答案任選其一都對(duì))4.8;

4.8s;

4.8s9、A1.0kg

blockisattachedtoaspringwithspringconstant16N/m

andisatrestonasmoothhorizontalplane.Itishitwithahammerandacquiresinstantaneouslyaspeedof0.40m/s.Thespeedoftheblockatx

=

A/2is

_____

m/s

(roundtotwodecimalplaces).

答案:0.3510、Anobjectofmassmisattachedtoahorizontalspring,stretchedtoadisplacementAfromequilibriumandreleased,undergoingharmonicoscillationsonafrictionlesssurfacewithperiod

.Theexperimentisthenrepeatedwithamassof4m.Theratio

ofthenewperiodofoscillationandtheoldperiodis_____

.

答案:(以下答案任選其一都對(duì))2;

2.0作業(yè)01PeriodicMotionWeek1Chapter13PeriodicMotion1、Week1-ThehomeworkofChpater13

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02MechanicalWavesUnitTest21、答案:2、答案:3、答案:4、Whileaguitarstringisvibrating,yougentlytouchthemidpointofthestringtoensurethatthestingdoesnotvibrateatthatpoint.Whichnormalmodescannotbepresentonthestringwhileyouaretouchingitinthisway?答案:n=

1,3,5,…5、答案:75.0m6、

Thesixstringsofaguitararethesamelengthandundernearlythesametension,buttheyhavedifferentthicknesses.Onwhichstringdowavestravelthefastest?答案:Thethinneststring.7、答案:98、答案:9、

Atravelingwaveispropagatinginanelasticmediumandattimet

theparticleatpositionP

hasthemaximumdisplacement.ThepotentialenergyoftheparticleatpositionP

is

_____(fillingin“maximum”,“minimum”,or“zero”).

答案:(以下答案任選其一都對(duì))ZERO;

zero10、Astretchedstringfixedattwoendshasamassof

0.08kg

andalengthof

8.00m.Thetensioninthestringis64.0N.Thereexistsastandingwaveonthestring.Forthethirdharmonic,thevibrationfrequencyis

Hz

(Keeponlytheintegerportion).

答案:15作業(yè)02MechanicalWavesWeek2Chapter15MechanicalWaves1、Week2-Thehomework1ofChpater15

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03SoundandHearingUnitTest31、Youuseanelectronicsignalgeneratortoproduceasinusoidalsoundwaveinair.Youthenincreasethefrequencyofthewavefrom100Hzto400Hz

whilekeepingthepressureamplitudeconstant.Whateffectdoesthishaveonthedisplacementamplitudeofthesoundwave?答案:Itbecomes1/4asgreat.

2、Atuningforkplacedovera0.57m

columnofairclosedonlyatitsbottomendproducesastandingwaveinthe3rdharmonic.Thespeedofsoundinairis342m/s.Whatisthefrequencyofthetuningfork?

答案:450Hz3、Astandingwaveiscreatedinanair-filledtubeopenatbothendswhenatuningforkoffrequency552Hz

isplacednearoneoftheopenends.Atuningforkoffrequency644Hz

producesthenexthigherharmonicforthistube.Assumethatthespeedofsoundinairis340m/s.Whatisthelengthoftheopentube?答案:1.85m4、Aflutehasalengthof58.0cm.Ifthespeedofsoundinairis343m/s,whatisthefundamentalfrequencyoftheflute,assumingitisatubeclosedatoneendandopenattheother?

答案:148Hz5、答案:6、AstoppedorganpipeoflengthLhasafundamentalfrequencyof

220Hz.Forwhichofthefollowingorganpipeswilltherebearesonanceifatuningforkoffrequency

660Hzissoundednexttothepipe?答案:AstoppedorganpipeoflengthL.7、Ifa

1000Hzsoundsourcemovesataspeedof50.0m/stowardalistenerwhomovesataspeedof30.0m/sinadirectionawayfromthesource,whatisthefrequencyheardbythelistener?(Thespeedofsoundis340m/s.)答案:1069Hz8、

Whentwotuningforksaresoundedatthesametime,abeatfrequencyof

5Hzoccurs.Ifoneofthetuningforkshasafrequencyof245Hz,thefrequencyoftheothertuningforkis

Hz.

答案:(以下答案任選其一都對(duì))250;

2409、SupposethatspeakerAemitsasinusoidalsoundoffrequency

500HzandspeakerBemitsasinusoidalsoundwaveoffrequency

1000Hz.Ifwilltheinterferencehappenbetweenthesetwowavesmeeting?

__(fillinyesorno)

答案:(以下答案任選其一都對(duì))No;

no;

NO10、Youwereatrestandapolicecarwithitssirenonwaspassingyouwithaconstantspeed.Youfoundthatthefrequenciesofthesirenwererespectively550Hz

and450Hz

whenthepolicecarwasmovingtowardandawayfromyou.Assumethatthespeedofsoundinairis

340m/s.Thespeedofthepolicecarwas

m/s.(Keeponlytheintegerportion)

答案:34作業(yè)02MechanicalWavesWeek3Chapter15MechanicalWaves1、Week3homework.

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作業(yè)03SoundandHearingWeek4Chapter16SoundandHearing1、Week4homework

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04TheNatureandPropagationofLightUnitTest41、Somecrystalsarenotisotropic:lighttravelsthroughthecrystalatahigherspeedinsomedirectionsthaninothers.Inacrystalinwhichlighttravelsatthesamespeedinthex-andz-directionsbutatafasterspeedinthey-direction,whatwouldbetheshapeofthewavefrontsproducedbyalightsourceattheorigin?答案:ellipsoidal,stretchedoutalongthey-axis.2、Theindexofrefractionforwaterisabout

n=4/3.Whathappenstolightwhenittravelsfromairintowater?答案:Itsspeeddecreasesto3c/4

anditswavelengthdecreasesbyafactorof3/4.3、Arayoflightindiamond(indexofrefraction2.42)isincidentonaninterfacewithair.Whereisthelargestangletheraycanmakewiththenormalandnotbetotallyreflectedbackintothediamond?答案:24.404、Apolarizerandananalyzerareorientedsothatthemaximumamountoflightistransmitted.ThenaturallightofintensityI

isincidentonthepolarizer.Whentheanalyzerisrotatedthrough45.00,whichistheintensityofthelightthroughtheanalyzer.答案:0.25I5、UnpolarizedlightofintensityI

isincidentuponthreepolarizers.Thetransmissionaxisofthefirstpolarizerisalongthez

-axis,thatofthesecondpolarizeris30°rotatedthrough

fromthe

z-axis,andthatofthethirdpolarizerisrotatedinthesamedirectionthrough75°

fromthez-axis.Whatisthelightintensityafterthelightbeampassesthroughthethirdpolarizer?答案:3I

/166、Aparallelbeamofunpolarizedlightinairisincidentatanangleof

54.5°(withrespecttothenormal)onaplaneglasssurface.Thereflectedlightiscompletelylinearlypolarized.Whatistheangleofrefracti