雨课堂学堂在线学堂云《Mechanics of Materials（辽宁科技）》单元测试考核答案

第1题Thenormalstressandshearstressonthesamesectionmustbevertical.()第2题Themainresearchobjectofmechanicsofmaterialsisthebar.()第3题Stressistheaverageinternalforceonthecrosssection.()第4题Internalforcereferstotheinteractionforcegeneratedinsideanobjectafteritisstressed.()第5题Themaintaskofmechanicsofmaterialsistostudythe()ofcomponents.AStrengthBToughnessCStabilityDStiffness正确答案：ACD第6题Thebasichypothesesofmechanicsofmaterialsare().AIsotropyassumptionBUniformityassumptionCElastic-plasticassumptionDContinuityassumption正确答案：ABD第7题Thestructureshowninthefigurewilldeformasfollowsundertheactionofexternalforce().AADRodTorsion,BCRodCompressionBADRodandBCRodCompressionCADRodBending,BCRodTensionDADRodBending,BCRodCompression第8题Thebasicmethodofmaterialmechanicstosolvetheinternalforceis().ASectionmethodBEnergymethodCSuperpositionmethodDAnalyticalmethod第9题Thescrewinthereamedholeboltconnectionisdeformedby().AAxialtensionandcompressionBShearCTorsionDPlanebending第10题Thecolumnofthebuildingisdeformedby().AAxialtensionandcompressionBShearCTorsionDPlanebending第11题Thedeformationofthegirderintheclassroomis().AAxialtensionandcompressionBShearCTorsionDPlanebending第12题Whenthevehicleisrunning,thedeformationofthedriveshaftis().AAxialtensionandcompressionBShearCTorsionDPlanebending第13题Whenthecraneliftsheavyobjects,thedeformationofsteelwireropeis().AAxialtensionandcompressionBShearCTorsionDPlanebending第14题Rodsrefertothemembersof().AThesizeinonedimensionismuchlargerthanthatintheothertwodimensionsBThesizeintwodimensionsismuchlargerthanthatinthethirddimensionCThesizesinthreedimensionsaresimilarDAcertainsectionisacircle第15题Inordertoensurethenormaloperationofthemachineorstructure,itisrequiredthattheyhavesufficientresistancetodeformation,i.e.().AStrengthBToughnessCStiffnessDStability第16题Forslenderstraightrodsundercompression,inordertoensuretheirnormaloperation,itisrequiredthattheycanmaintaintheoriginalbalancestate,i.e.theyarerequiredtohavesufficient().AStrengthBToughnessCStiffnessDStability第17题Inordertoensurethenormaloperationofthemachineorstructure,itisrequiredthateachcomponenthassufficientresistancetodamage,i.e.theyhaveenough().AStrengthBToughnessCStiffnessDStability第18题Whentheinternalforceissolvedbysectionmethod,anequilibriumequationisestablishedfor().ALeftsectionBRightsectionCLeftorrightsectionDWholememberbar第19题Inthefollowingfourmaterials,()cannotapplytheisotropicassumption.AStainlesssteelBGlassCThree-plyboardDCastiron第20题Isotropyisconsideredthatthematerialhasthesame()inalldirections.AMechanicalpropertyBExternalforceCDeformationDDisplacement第21题Assumptionofuniformity:Itisbelievedthat()ateachpointinsidethematerialarethesame.AStressBStrainCDisplacementDMechanicalproperty第22题Strength,rigidityandstabilityofmembers()AOnlyrelatedtothemechanicalpropertiesofmaterialsBOnlyrelatedtotheshapeandsizeofcomponentsCRelatedtobothDUnrelatedtoboth第23题Theapplicablescopeofcross-sectionmethodis()AItisonlylimitedtostraightbarswithuniformsectionBItisonlylimitedtothebasicdeformationofstraightbarsCItisonlylimitedtotheelasticdeformationofmembersDItisgenerallyapplicabletoelasticandplasticdeformation,basicdeformationandcombineddeformationofbarswithuniformsectionandvariablecross-section(straightbarsandcurvedbars).第24题Amongthepracticalproblemslistedbelow,whichoneisastrengthproblem?()AFlagpolehasunrecoverablepermanentdeformationduetoexcessivewindforceBBicyclechainslipswhentheelongationexceedstheallowablevalueCUnevenwearofgearsandbearingscausedbyexcessivedeformationoftransmissionshaftDSlimjackscrewisbentduetoexcessivepressure第25题Whichofthefollowingpracticalproblemsisastabilityproblem?()AFlagpolesuffersfromunrecoverablepermanentdeformationduetoexcessivewindforceBBicyclechainisstretchedbeyondtheallowablevalueandslipsCBridgepavementcracksduetovehicleoverloadDSlimjackscrewisbentduetoexcessivepressure第26题Amongthepracticalproblemslistedbelow,()isastiffnessproblem.AFlagpolesuffersfromunrecoverablepermanentdeformationduetoexcessivewindforceBBicyclechainisstretchedbeyondtheallowablevalueandslipsCBridgepavementcracksduetovehicleoverloadDSlimjackscrewisbentduetoexcessivepressure第27题Twophysicalquantitiesrepresentingthedegreeofdeformationatapointare().ALineardisplacementandangulardisplacementBLongitudinaldeformationandtransversedeformationCLinearstrainandshearstrainDBasicdeformationandcombineddeformation第28题Whichofthefollowingstatementsaboutstressiscorrect?().ATheshearstressisparalleltothesection,representedbyBThenormalstressisperpendiculartothesection,representedbyCThenormalstressisparalleltothesection,representedbyDTheshearstressisperpendiculartothesection,representedby第29题Thebasicassumptionsofmechanicsofmaterialsdonotinclude().AUniformityandcontinuityBIsotropyCRodpiecesmustbestraightDSmalldeformation第30题Amongthefollowingconclusions,()iscorrect.AThetaskofmechanicsofmaterialsistostudythemechanicalproblemsofvariousmaterialsBThetaskofmechanicsofmaterialsistodesigncomponentsorpartsundertheprincipleofensuringsafetyCThetaskofmechanicsofmaterialsistodesigncomponentsorpartsundertheprincipleofstrivingforeconomyDThetaskofmechanicsofmaterialsistoprovidebasictheoriesandmethodsofanalysisandcalculationfordesigningcomponentsorpartsundertheprincipleofsafetyandeconomy第1题Thepullrodsubjectedtoaxialforcewillshortentransverselyafteraxialelongation,whichisduetotheexistenceoftransversestress.()第2题Inanyaxialtensionmember,themaximumnormalstressoccursonthesectionwiththelargestaxialforce.()第3题Inanaxialtensilemember,ifthedisplacementofonecrosssectionisgreaterthanthatofanothercrosssection,thestressonthiscrosssectionmustalsobegreaterthanthatontheothercrosssection.()第4题Incaseofaxialtension,thenormalstressonthecrosssectionbecomesdirectlyproportionaltothelongitudinallinearstrain.()第5题Whentheinternalforceiscalculatedbysectionmethod,anypartofthecutmembercanberetainedforequilibriumcalculation.()第6题Provisionsonpositiveandnegativesignsofpositivestressonthecrosssectionofaxiallystretchedorcompressedrodpieces:ifthedirectionofpositivestressisconsistentwiththeexternalnormaldirectionofthecrosssection,itispositive;otherwise,itisnegative.Suchprovisionsareconsistentwiththosefordeformationofrodpieces.()第7题Fortherodfixedatoneend,undertheactionofaxialexternalforce,theinternalforcediagramcanbedrawnwithoutfindingouttheconstraintreaction.()第8题Iftherearemorethantwoexternalforcesactingalongtheaxisdirectionofthememberbar,theaxialforceoneachcrosssectionofthememberbarisdifferent.()第9题Whenthelow-carbonsteelspecimensyieldintension,asliplineatanangleof450withtheaxisappearsontheirsurface,whichisrelatedtothemaximumshearstress.()第10题Thereisonlynormalstressandnoshearstressintheaxiallystretched()memberbar.()第11题Forstraightmemberswithuniformcross-section,axialtensionandcompressiondeformationwilloccuraslongastheactionlineofresultantforceofexternalforcesisparalleltotheaxis.()第12题Thevariablecross-sectionrodADissubjectedtoconcentratedforce,andthecross-sectionalareaofsectionABisgreaterthanthatofsectionBD.Asshowninthefigure,whichofthefollowingstatementsaboutstressarecorrect?().AThestressofsectionABisequaltothatofsectionBC.BThestressofsectionABislessthanthatofsectionBC.CThestressofsectionBCisequaltothatofsectionCD.DThestressofsectionBCislessthanthatofsectionCD.正确答案：BD第13题Thevariablecross-sectionrodADissubjectedtoconcentratedforce,andthecross-sectionalareaofsectionABisgreaterthanthatofsectionBD,asshowninthefigure.Whichofthefollowingdescriptionsaboutaxialforceiscorrect?().ATheaxialforceofsectionABisequaltotheaxialforceofsectionBCBTheaxialforceofsectionABislessthanthatofsectionBCCTheaxialforceofsectionBCisequaltothatofsectionCDDTheaxialforceofsectionBCislessthanthatofsectionCD正确答案：AD第14题Bar(),thesmallerthemodulusofelasticityofthematerial,thegreaterthedeformation.AUnderacertainloadBWhenthesizeandshapeareconstantCWhenthethicknessandloadareconstantDThelengthandloadremainunchangedwithintheproportionallimit第15题Intheaxialtensiletestofsteelpipe,severaldeformationphenomenaareputforwardbysomepeople.Ithasbeenverifiedthatthecorrectdeformationis().AWhentheouterdiameterincreases,thewallthicknessdecreasesBWhentheouterdiameterincreases,thewallthicknessincreasesCWhentheouterdiameterdecreases,thewallthicknessincreasesDWhentheouterdiameterdecreases,thewallthicknessdecreases第16题Thetworoundbarsaremadeofthesamematerial.RodIisasteppedbarandrodIIisanequalstraightbar,whicharesubjectedtotensileforceP(asshowninthefigure).Byanalyzingthedeformationofthetwobars,itcanbeknownthattheconclusionofelongation()ofrodIiscorrect.A2timestheelongationofrodIIBlessthantheelongationofrodIIC2.5timestheelongationofrodIIDequaltotheelongationofrodII;第17题Undertheactionofaxialforce(asshowninthefigure),thedeformationofBCsectionsofapolewithconstantsectionwill().AElongation,whichistwicetheshortenedamountofsectionAB(orCD)BZeroCItistheelongationofitsownlengthLundertheactionofforcePDShortening,whichisequaltotheshortenedamountofsectionAB(orCD).第18题Inthetensiletestoflowcarbonsteel,ifthesampleisstretchedtothestrengtheningstageforunloading,theP-ΔLcurveoftensiondiagramshallbeunloadedtozeroalong().AOriginalstretchdiagramcurveBAnycurveCAnystraightlineDObliquestraightlinenearlyparalleltotheelasticstage第19题Theaxialforceoftheaxialtensionorcompressionrodis().APerpendiculartotheaxisandpassingthroughthecentroidofsectionBPerpendiculartothecrosssectionandpassingthroughthecentroidofsectionCPerpendiculartotheaxisandpointinginthesamedirectionasthepositivedirectionofcoordinateDPerpendiculartothecrosssectionandpointinginthesamedirectionasthepositivedirectionofcoordinate第20题Forasquarecross-sectionlowcarbonsteelstraightpullrod,itsaxialtensileforceis3600N.Iftheallowablestressis100Mpa,thesidelengthofthecrosssectionofthepullrodshallbeatleast().A36mmB6.77mmC60mmD6mm第21题Themainstrengthindexofthematerialis().AProportionallimitandelasticlimitBElasticlimitandyieldlimitCYieldlimitandstrengthlimitDElasticlimitandstrengthlimit第22题TheapplicableconditionofHooke'slawis().AOnlyapplicabletoplasticmaterialsBOnlyapplicabletoaxialtensionCThestressdoesnotexceedtheproportionallimitDThestressdoesnotexceedtheyieldlimit第23题Inthetensiletestofcarbonsteel,iftheinstantaneouscross-sectionalareaofthesampleisusedtocalculatethestrengthlimit,itsvaluewillbecomparedwiththeresultcalculatedbyusingtheoriginalcross-sectionalarea().ANobigdifferenceBSmallCLargeDMeaningless第24题Inthewholetensileprocessoflowcarbonsteel,thestressrangewhereonlyelasticdeformationoccursinthematerialshallnotexceed().AProportionallimitBElasticlimitCYieldlimitDStrengthlimit第25题Elongationisusedtomeasurethe()performanceofmaterials.AElasticityBPlasticityCElastic-plasticDStrength第26题Ifthreedifferentcross-sectionalshapesareselectedforaxiallystretchedstraightbars:round,squareandhollowcircle,andthematerialconsumptioninthethreecasesiscompared,then().ASquaresectionisthemosteconomicalBCircularsectionistheleasteconomicalCHollowcircularsectionisthemosteconomicalDThesamematerialsareusedforthethree第27题Aftercoldhardeningtreatment,the()ofsteelisbasicallyunchanged.AElasticmodulusBProportionallimitCDuctilityDSectionshrinkageAnswer:A第28题Foraxialtensionrods,thesectionwiththemaximumnormalstressandthesectionwiththemaximumshearstressare().Acrosssectionand45°obliquesectionBallcrosssectionsC45°obliquesectionandcrosssectionDall45°obliquesections第29题Therearetwoconclusionsaboutthemechanicalpropertiesofcastiron:(1)Shearcapacityispoorerthantensilecapacity;(2)Compressivestrengthishigherthantensilestrength.Where,().A(1)Correct,(2)IncorrectB(2)Correct,(1)IncorrectCBoth(1)and(2)arecorrectDBoth(1)and(2)areincorrect第30题Whendeterminingthesafetyfactor,()shallnotbeconsidered.AQualityofmaterialsBCalculationaccuracyofworkingstressCWorkingconditionsofcomponentsDLoadmagnitudeChapter3Assignment第1题Ingeneral,extrusionoftenoccurssimultaneouslywithshear.However,itshouldbepointedoutthattheextrusionstressisdifferentfromtheshearstress,whichisnotaninternalforceperunitareainsidethecomponent.()第2题Inthepracticalcalculationofextrusion,aslongastheactualcontactsurfaceareaofthecomponentisusedtocalculatetheextrusionstress,theresultwillbeconsistentwiththeactualextrusionstressofthecomponent.()第3题Inthepracticalcalculationofextrusion,theareaoftheextrudedsurfacetakenistheprojectedareaoftheextrusioncontactsurfaceinthedirectionverticaltotheextrusionforce.()第4题Afterthetwosteelplatesareconnectedbybolts,localpressurebearingwilloccuronthecontactsideoftheboltandthesteelplate,whichiscalledextrusion.Whentheextrusionforceistoolarge,itmaycauseboltflatteningorsteelplateholeedgewrinkling,resultinginlooseconnectionandfailure.()第5题Therearemultipleshearplaneswiththesameareaonthecomponent.Whenthematerialiscertain,onlytheshearplanewithlargershearforcecanbecheckedtochecktheshearstrengthofthecomponent.()第6题Thepapercutwithscissorsandthevegetablescutwithkniveswereshearedanddamaged.()第7题Iftwoequal,oppositeandparallelexternalforcesactonthecomponent,thecomponentwilldefinitelyproducesheardeformation.()第8题Whenthesteelplateissheared,thestressgeneratedbytheexternalforceisslightlygreaterthantheyieldlimitofthematerial.()第9题Fortheconnectingpartoftworods,ifthedimensionsateachpositionareshowninthefigure,().ATheareaofshearsurfaceisbcBTheareaofextrusionsurfaceisbcCTheareaofshearsurfaceisabDTheareaofextrusionsurfaceisab正确答案：BC第10题Whichofthefollowingstatementsiscorrect?()AExtrusionstressisthepressuredistributedonthecontactsurfaceoftwomembersBBothextrusionstressandcompressivestressareinternalforcesonunitareaofinternalsectionofmemberCCompressivestressistheinternalforceonunitareaofinternalsectionofmemberDExtrusionstressequalstosheardividedbytheareaofcontactsurface正确答案：AC第11题Inthepracticalcalculationofshear,itisassumedthattheshearstressis()distributedontheshearplane.ALinearBUniformCParabolaDHyperbolic第12题Whencalculatingtheextrusionstress/ontheboltedextrusionsurface,itrefersto().AAreaofsemi-cylindricalsurfaceBCross-sectionalareaoverdiameterandperpendiculartoextrusionforceCAreaofcylindricalsurfaceDAreaofcrosssection第13题Asshowninthefigure,placeawasherbetweentheplateandthetensionedbolttoincrease().BoltPlateWasherATensilestrengthofboltBExtrusionstrengthofboltCShearstrengthofboltDExtrusionstrengthofplate第14题Themaximumextrusionstressofthehookasshowninthefigureis().AP/(dt)BP/(2pdt)CP/(pdt)DP/(2dt)第15题Therivetedpartsshowninthefigureare().ATheextrusionstressofsteelplateisgreaterthanthatofaluminumrivetBTheextrusionstressofsteelplateislessthanthatofaluminumrivetCTheextrusionstressofsteelplateisequaltothatofaluminumrivetDItisimpossibletodeterminetherelationshipbetweentheextrusionstressofsteelplateandtheextrusionstressofaluminumrivet第16题Whencalculatingthestrengthofconnectors,theshearplaneandextrusionplane()aresubjecttoexternalforce.AVerticalandparallelrespectivelyBBothparallelCParallelandverticalrespectivelyDBothperpendicular第17题Thepracticalcalculationofshearstressinconnectorsisbasedontheassumption().ATheshearstressisevenlydistributedontheshearsurfaceBTheshearstressdoesnotexceedtheshearproportionallimitofthematerialCTheshearsurfaceiscircularorsquareDTheareaoftheshearsurfaceisgreaterthanthatoftheextrusionsurfaceChapter4Assignment第1题Whenthetwosolidroundshaftsaretwistedanddeformed,theirmaterials,diametersandmomentofexternalcouplearethesame.However,duetothedifferentlengthsofthetwoshafts,thetorsionangleperunitlengthoftheshortshaftislarger.()第2题ThepolarmomentofinertiaofahollowcircularshaftsectionwithaninnerdiameterdandouterdiameterDcanbecalculatedbytheformulaIp≈0.1(D4-d4),andthetorsionalsectioncoefficientcanbecorrespondinglycalculatedbytheformulaWt≈0.2(D3-d3).()第3题5dcanbecalculatedaccordingtothestrengthcondition.()第4题Thematerialandlengthofthesolidshaftandthehollowshaftarethesame.Undertheconditionofequaltorsionalstrength,theweightofthehollowshaftislight,soitisreasonabletoadoptahollowroundshaft.Thethinnerthewallthicknessofhollowshaftis,thehigherthematerialutilizationratewillbe.However,ifthewallofhollowcircularshaftistoothin,itwilleasilyproducelocalwrinkles,whichsignificantlyreducesitsload-bearingcapacity.()第5题Themaximumshearstressonthecrosssectionoftwocircularshaftswiththesamethicknessandlength,oneisasteelshaftandtheotherisanaluminumshaft,arethesamewhentheyaresubjectedtoelastictorsionaldeformationunderthesameexternalcoupleaction.()第6题Thediametersofgearshaftsintheprimaryreductionboxarenotequal.Underthestrengthconditionsmeetingthesameconditions,thediameterofhigh-speedgearshaftislargerthanthatoflow-speedgearshaft.()第7题Whenahollowroundshaftissubjectedtotorsionaldeformation,themaximumshearstressofthewholeshaftexistsattheouteredgeofitsdangeroussection,whiletheshearstressattheinneredgeofthedangeroussectioniszero.()第8题Thesignoftorquecanbespecifiedasfollows:usingtheright-handscrewrule,fourfingersindicatetherotationdirectionoftorque.Whenthethumbpointingisinthesamedirectionastheexternalnormallineofthesection,thespecifiedtorqueispositive;otherwise,thespecifiedtorqueisnegative.()第9题Aslongasthealgebraicsumofallexternalcouplemomentsactingontheleftorrightpartofacrosssectionofatorsionbarisknown,thetorqueonthatcrosssectioncanbedetermined.()第10题Torqueisthecouplemomentofdistributedinternalforceinteractionbetweentheleftandrightpartsofacrosssectionofthetorsionbar.()第11题Asteelshaftandarubbershafthavethesamediameterandthesameforce.Ifbothshaftsareintheelasticrange,theshearstressontheircrosssectionsisalsothesame.()第12题Theplanehypothesisofacircularcross-sectionbarintorsionisonlyvalidwithinthelinearelasticrange.()第13题Whenastraightrodwithuniformsectionistwisted,thecrosssectionofthedeformedrodremainsplane,anditsshapeandsizeremainunchanged.()第14题Torquereferstotheinternalcouplemomentonthecrosssectionwhentherodistwisted.Thetorqueisonlyrelatedtotheexternalcouplemomentbornebytherod,andhasnothingtodowiththematerialoftherodandtheshapeofthecrosssection.()第15题Thereciprocalshearstresstheoremisonlyapplicabletopureshear.()第16题Whentheroundshaftistwisted,thetorsionangleperunitlengthhasnothingtodowiththeshaftlength.()第17题Pointsonthecrosssectionareinastateofpureshearstresswhenthecircularshaftistwisted.()第18题Whenthecircularsectionbaristwisted,boththecrosssectionandthelongitudinalsectionremainplane.()第19题Iftworoundshaftsmadeofdifferentmaterialshavethesamelength,cross-sectionaldiameterandactingtorsioncouplemoment,theirmaximumrelativetorsionanglesarealsothesame.()第20题Aftertheroundstraightpolewithuniformsectionistwistedanddeformed,thecrosssectionofthepoleremainsplane,anditsshapeandsizeremainunchanged.()第21题Thehigherthespeedofthetransmissionshaftis,thegreaterthetorqueonthecrosssectionoftheshaftwillbe.()第22题Thereciprocaltheoremofshearstress().ADerivedaccordingtoequilibriumconditionsBDerivedonthebasisofconsideringbalance,geometryandphysicalfactorsCOnlyapplicabletotorsionbarsDApplicabletovariousstressedbars正确答案：AD第23题Forfourhollowshaftswithequalcross-sectionalareasbutdifferentinnerandouterdiameterratios,theexternalcouplemomentatbothendsduringtorsionism,ofwhichtheshaftwithaninnerandouterdiameterratioof()hasthelargestbearingcapacity.A0.8B0.6C0.5D0.1第24题Ahollowsteelshaftandasolidaluminumshafthavethesameouterdiameter.Bycomparingtheirtorsionalsectionmodulus,itcanbeknownthat().AThehollowsteelshaftislargerBThesolidaluminumshaftislargerCTheirvaluesarethesameDTheyarerelatedtotheshearmodulusoftheshaft第25题Theexternalcouplemomentofthedrivingwheelonatransmissionshaftism1,andtheexternalcouplemomentsofthedrivenwheelarem2andm3,andm1=m2+m3.Installthedrivinggearbetweentwodrivengearsatfirst,andthenexchangethepositionsofthedrivinggearandadrivengear.Themaximumtorqueinthedriveshaftwillbe().ADecreaseBIncreaseCRemainunchangedDChangetozero第26题Thepowertransmittedbythevehicletransmissionmainshaftremainsunchanged.Whenthespeedoftheshaftisreducedtohalfofitsoriginalvalue,thecouplemomentoftheexternalforcecouplebornebytheshaftwill()comparedwiththatbeforethespeedisreduced.AdoubleBtripleChalveDunchanged第27题Ahollowroundshaft(theratioofitsinnerandouterdiametersd/D=0.5)istwisted.Whenboththeinnerandouterdiametersarereducedbyhalf,thetorsionangleperunitlengthoftheroundshaftis()timestheoriginalvalue.A16B8C4D2第28题Therearetworoundshaftsofthesamematerial,oneisasolidshaftwithdiameterD1andtheotherisahollowshaftwithaninner-outerdiameterratioofd2/D2=0.8.Ifthetorqueandtorsionangleperunitlengthofthetwoshaftsarethesame,theirdiameterratioD2/D1=().A1.52B1.34C1.14D0.96第29题Forsolidroundshaftsandhollowroundshaftsmadeofthesamematerial,iftheirlengthandcross-sectionalareaarethesame,()hasgreatertorsionalrigidity.AHollowroundshaftBSolidroundshaftCThetwoarethesameDUnabletojudge第30题Asshowninthefigure,()ofthemaximumtorquevalueontheroundshaft.A6kNmB7kNmC8kNmD9kNmChapter5Assignment第1题Thedimensionoftheradiusofinertiais()powerofthelength.AfirstBsecondCthirdDfourth第2题Thedimensionofthepolarmomentofinertiais()powerofthelength.AfirstBsecondCthirdDfourth第3题Thedimensionofstaticmomentisthe()poweroflength.AfirstBsecondCthirdDfourth第4题Thedimensionofthemomentofinertiais()powerofthelength.AfirstBsecondCthirdDfourth第5题Ifthesectionaldrawinghasanaxisofsymmetry,()ofthedrawingtoitsaxisofsymmetry.AStaticmomentiszeroandinertiamomentisnotzeroBStaticmomentisnotzeroandinertiamomentiszeroCBothstaticmomentandinertiamomentarezeroDNeitherstaticmomentnorinertiamomentiszero第6题Inthegeometricpropertiesofplanefigures,thevalueof()canbepositive,negativeorzero.APolarmomentofinertiaBPolarmomentofinertiaandinertiamomentCMomentofinertiaDStaticmoment第7题Inthefollowingconclusionsaboutplanefigures,()isincorrect.AThesymmetryaxisofthegraphmustpassthroughthecentroidBTheintersectionpointoftwosymmetryaxesofthegraphmustbethecentroidCThestaticmomentofthegraphtothesymmetryaxisiszeroDTheaxisthatmakesthestaticmomentzeroisthesymmetryaxisChapter6Assignment第1题Attheconcentratedcoupleactiononthebeam,thebendingmomentdiagramhasasuddenchange,andthecorrespondingshearforcediagramisahorizontalline,whichchangesfrompositivetonegativeorfromnegativetopositive,butitsabsolutevaluesarethesame.()第2题Whencheckingthecorrectnessofthedrawnsheardiagramfromlefttoright,itcanbeseenthatwhereconcentratedforceisapplied,thesheardiagramsuddenlychanges,andthemagnitudeofthesuddenchangevalueisthesameasthedirectionandconcentratedforce.Iftheconcentratedforceisupward,thesheardiagramsuddenlychangesupward,andthesuddenchangevalueisthemagnitudeoftheconcentratedforce.()第3题Thebendingmomentdiagramofthecantileverbeamunderuniformlydistributedloadisanupwardconvexquadraticparabola,andtheapexofthiscurvemustbeatthepointcorrespondingtothefreeendofthecantileverbeam.()第4题Wheretheshearforceonabeamiszero,theslopeofthecorrespondingbendingmomentdiagramisalsozero;conversely,iftheslopeofthebendingmomentdiagramforabeamiszero,thecorrespondingshearforceonthebeamisalsozero.()第5题Thebendingmomentvalueofacertainpointonthebendingmomentdiagramofthebeamiszero,andtheshearforcevalueontheshearforcediagramcorrespondingtothispointmustalsobezero.()第6题Thedistributedloaddirectioninacertainsectionofthebeamisdownward,whichindicatesthatthebendingmomentcurveisconvexupwardanditsbendingmomentvaluemustbepositive.()第7题Whenthebendingmomentdiagramofthebeamisaquadraticparabola,ifthedistributedloaddirectionisupward,thebendingmomentdiagramisanupwardconvexparabola.()第8题Ifthebendingmomentone