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