理论力学知到章节答案智慧树2023年长安大学

理论力学知到章节测试答案智慧树2023年最新长安大学绪论单元测试Afterthe20thcentury,physicsdividedintotwobranches:modernphysicsandmodernmechanics.（）

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对Whoisknownasthe“fatherofmechanics”（）.

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Archimedes第一章测试Thereisacoplanarconcurrentforcesystemactingonarigidbody,andtheforcevectorrelationshipoftheforcesisshowninFigure，Itcanbeknownthattheresultantforceoftheforcesystemiszeroandtheforcesystemisinequilibrium.（）

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错Asisshowninthefigure,theforcePonACcanbemovedtoBCaccordingtothetransmissibilityoftheforce.（）

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错Arigidbody,subjectedtoforceswhichareactedontwopoints,iscalledDouble-forceBody.（）

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错andmeansthesame.（）

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错TheFBDshowninthefigureiscorrect.（）

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错第二章测试Thereisacoplanarconcurrentforcesystemactingonarigidbody,andtheforcevectorrelationshipoftheforcesisshowninFigure，Itcanbeknownthatthereductionoftheforcesystemis（）.

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inequilibriumAsisshowninthefigure,ifthecoupleMactingonACismovedtoBC,themagnitudeofthereactionforcesatA,BandC（）.

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AllunchangedThemagnitudeanddirectionoftheforcecanbedeterminedbytheanalyticalexpressionoftheforce.（）

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对TheweightoftherodABandCDandthefrictionisignored,ifthemomentofthecoupleactingontherodABis,inordertokeepthesystembalanced,themomentofthecoupleactingontherodCDisisshowninthefigure,anditsmomentvalueis（）.

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****Asisshowninthefigure,thecoupleMactsontheACrod,themagnitudeofthereactionforceofsupportAis（）.

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10kN第三章测试TakinganytwopointsAandBintheactionplaneoftheconplanarforcesystem,iftheprincipalmomentsoftheforcesystemaboutthesetwopointsarebothzero,theforcesystemcannotbecomposedintoaforce.（）

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错Aconplanarforcesystemcannotbecomposedintoacoupleiftheprincipalmomentoftheforcesystemaboutanypointisequaltozero.（）

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对ThearbitraryforcesystemofacertainplaneissimplifiedtopointO,andR’=10N,MO=10N·cmareobtained.Thedirectionsareshowninthefigure.ThenthesimplificationresultofthisforcesystemtopointAis（）.

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Rˊ=10N，MA=0AnarbitraryforcesysteminaplaneissimplifiedtopointO,aforceR’andacouplewithcouplemomentMOareobtainedasshowninthefigure,thenthefinalsimplificationresultoftheforcesystemis（）.

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AresultantforceatsomepointontheleftofOShownasthefigure,theequilateraltriangleplatewithsidelengthof1misaffectedby,F2=2kN,.Thenthefinalreductionoftheforcesystemis（）.

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Aresultantforcewithmagnitude1kN,actingatpointA,←第四章测试Asshowninthefigure,ifthecompositebeamisbalancedunderthegeneralcoplanarforcesystem,nineindependentbalanceequationscanbelistedifABbar,ACbarandtheentiresystemaretakenastheresearchobjects,right?（）

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错Therearefiveindependentequilibriumequationsforanoncoplanarforcesysteminwhichtheactionlinesoftheforcesareontwoparallelfixedplanes.（）

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对Thereareatmostthreeindependentequilibriumequationsforanoncoplanarforcesysteminwhicheachforceactionlineisperpendiculartoafixedplane.（）

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对Inthefigure,a=1m,acouplewithamomentofM=10kN·misactedonthestructure,thereactionforceoffixedhingesupportDwithoutregardingtotheweightofeachbaris（）.

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10kN,→ThestructureshowninthefigureiscomposedofbarsAB,DEandBD,theweightofeachbarisnotcounted.D,CandBareallhingedconnections,andendAisfixedsupport.Given:q（N/m）,M=qa2（N·m）,P=qa（N）,anddimensionsasshowninfigure.ThentheinternalforceofrodBDis（）.

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****第五章测试TheblockweighsW,andanexternalforceFactsontheblockwiththeactionlineoutsideoftheangleoffriction,asshowninthefigure.Givenθ=25°,angleoffrictionφm=20°,F=W,thentheblockisatrest.（）

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对Asshowninthefigure,splitwithasteelwedgeandtheangleoffrictionbetweenthecontactsurfacesisφm.Inordertomakethewedgedonotslipoutaftersplitting,theangleθshouldbe（）.

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θ≤2φmInthecaseoffriction,theanglebetweenthetotalreactionforceandthenormalreactionforceiscalledtheangleoffriction.（）

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错Asshowninthefigure,givenW=100kN,P=80kN,andthecoefficientofstaticfrictionisfs=0.2,thentheblockwillmoveupward.（）.

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错RectangularcabinetasshowninthefigureweightsG,andcenterofgravityCisinitsgeometriccenter.Thecoefficientofstaticfrictionisfsbetweenthecabinetandtheground.AhorizontalforceFisappliedtothecabinetonright,thentheminimumvalueofFrequiredtomakethecabinetbeinequilibriumis（）.

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min{Gfs,Ga/2h}第六章测试Ifthevelocityofamovingpointwhichisdoingplanecurvilinearmotionisconstant,thevelocityvectorisperpendiculartotheaccelerationvector.（）

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对TherightanglerigidbarOABattheinstantshowninthefigurehasω=2rad/sandα=5rad/s2.IfOA=40cm,AB=30cm,thetangentialaccelerationandnormalaccelerationofpointBare（）.

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250m/s2,200m/s2Asshowninthefigure,givenAB∥O1O2,AB=O1O2=L,AO1=BO2=r,ABCDisarectangularplate,andAD=BC=b,AO1rodrotatesaroundthefixedaxisO1atauniformangularvelocityω,thenthevelocityandaccelerationofthecenterofgravityC1oftherectangularplateare（）.

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v=rω,a=rω2ThegearwithradiusRrotatesaroundthefixedaxisO,anddrivestherackABtomove.Giventhattheangularvelocityofgearisωandtheangularaccelerationofgearisαattheinstantshownasfigure.PointConthegearisincontactwithpointC’ontherack,thentheaccelerationofpointCandtheaccelerationofpointC’are（）.

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****ThesquareplateABCDisrotatingaroundafixedaxis,andtherotationalaxisisperpendiculartotheplatesurface.ThevelocityofpointAisvA=10cm/sanditsaccelerationis.Thedirectionsareshowninthefigure.Thentheangularvelocityofthesquareplateis（）.

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1rad/s第七章测试ThewheelwithradiusRrotatesclockwiseaboutaxisOatauniformangularvelocityω,anddrivesrodABtorotateaboutaxisA.TakethecenterofwheelCasmovingpoint，androdABasthereferenceobjecttowhichthemovingreferenceframeisfixedlyattached.Whichofthefollowingstatementsistrue?（）

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ThedirectionofthetransportvelocityisperpendiculartoAC.;TheabsolutemotiontrajectoryisthecirclearoundO.;TherelativemotiontrajectoryisastraightlineparalleltoAB.Atthismomentshowninthisfigure,rodOCDrotatesaroundaxisOatanangularvelocity,makingrodABmovealongtheverticaldirection.OC=Lisknown.TakepointAontheABrodasthemovingpoint,andthemovingreferenceframeisfixedontherodOCD.Atthepositionshown,φ=45°,thetransportvelocityofpointAis（）.

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****Asshowninthefigure,,therodrotatesaboutfixedaxisAatauniformangularvelocityω=2rad/s.ThereisasleeveContherodAB,whichishingedwiththerodCD,andallpartsofthemechanismareinthesameplane.ThesleeveCisselectedasthemovingpoint,andtheABrodisthemovingreferenceframe.Whenφ=60°,thetransportvelocityis（）.

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****Inacrankslidemechanism,thecrankOAwithlengthl=0.2mrotatesanticlockwiseaboutaxisOatauniformangularvelocityof3rad/s.ThecrankendAishingedwiththeslidingblockAwhichcanslidealongthegroovetodrivetheT-shapedslidewayBCforreciprocatingtranslation.Iftheanglebetweenthecrankandtheaxisoftheslideis30°atthisinstant,theaccelerationofT-shapedslidewayBCis（）.

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****TakepointBonBCrodasthemovingpoint,andthemovingreferenceframeisfixedtotheflat-bottomcam.Theaccelerationvectorisshowninthefigure.IfthetheoremofcompositionofaccelerationsisprojectedtoOBdirection,writetheprojectionformula,whichofthefollowingequationsiscorrect?（）

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****第八章测试TheequilateraltriangleplatewithsidelengthLmovesinitsownplane.GiventheaccelerationofpointArelativetopointBisaAB,whosemagnitudeisaanddirectionisparalleltoCB,thentheangularvelocityofthetriangleplateatthisinstantis（）.

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****Thevelocityoftwoparallelracksarev1=5m/sandv2=2m/s.Thereisagearinthemiddleofthetwotracks.R=0.5m.Theangularvelocityofthegearis（）.

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3rad/s(clockwise)ThinplateBCissupportedbytwoequallengthbarsABandCD,anditmovesinitsownplane.Attheinstantasshowninfigure,ABBC,BCCD.IfbarABrotatesatauniformangularvelocityω,thenatthisinstant（）.

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;Theaccelerationoftheinstantaneouscenterofvelocitiesmayalsobezero.（）

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错Crank-rodmechanismisshowninfigure,known:AB=OA=L,φ1=φ2=φ,uniformangularvelocityω.Theradiusofthewheelisr,anditrollswithoutslippingalongthefixedhorizontalplane.ThentheangularvelocityandangularaccelerationofwheelBare（）.

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****第九章测试ObjectMwithweightP=10N,isplacedonasmoothinclinedplane,whichcanrotateabouttheY-axis.RopelengthL=2m,inclinedangleθ=30°,andtheuniformrotationalspeedn=10r/min,thenthetensionoftheropeis（）.

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6.68NIftwoparticleshavethesamemassandareacteduponbythesameforce,theirvelocitiesandaccelerationsareequalatanyinstant.（）

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错Asshowninthefigure,thetrolleymovesupwardalongtheinclinedplanewiththeuniformaccelerationa,andanobjectAwiththemassmisplacedontheflattopofthetrolleytomovewiththetrolley.Inordertopreventtheobjectfromfallingofffromthetrolley,theminimumstaticfrictioncoefficientbetweentheobjectandthetrolleyshouldbe（）.

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****Asshowninthefigure,asmallballwithmassmsuspendedbytworopesisatrest.IfropeAiscut,thetensionofropeBatthisinstantis（）.

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****ThesmallringslidesfromthetopAofthefixedsmoothhalfcylinderwithoutinitialvelocity,asshowninthefigure,thenthepositionangleφatwhichtheringisdetachedfromthehalfcylinderis（）.

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48.2°第十章测试ThelengthoftherodABis40cm,theoriginallengthofthespringis20cm,thespringconstantk=200N/m,andthemomentofcoupleM=180Nm.WhentherodABmovesfromthepositionshowninthediagramtothehorizontalpositionA’B,findtheworkoftheelasticforceandtheworkofthecoupleM.（）

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1.46J,-30πJDeterminethemomentofinertiaofahomogeneousdisk(massm,radiusr)abouttheO-axis,wherethedistancebetweentheO-axisandthemasscenterCise.（）

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****ThehomogeneousbarAB,withmassmandlengthl,rotatesaboutaxisAwithangularvelocityω,andaxisAmoveshorizontallywithvelocityv.FindthekineticenergyofbarABatthemomentshowninthefigure.（）

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****Ifthependulumisreleasedfromthehorizontalposition,thevelocityofitsbobintheverticalpositionis（）.

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3.8m/sThecenterofahomogeneouswheel(massm,radiusr)hasthevelocityv0intheinitialpositionasshowninthefigure.Thewheelrollswithoutslipping.Calculatethevelocityvofitscenterinthepositionshownbythebrokenlines.（）

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****第十一章测试ThesmallballMwithweightQisfixedonathinhomogeneousrodoflengthlandweightP.Theotherendoftherodishingedontheroofofthecarmovingwithv.TherodOMrotatescounterclockwisearoundaxisOatanangularvelocityω.Thenthemagnitudesofthemomentumsoftherodandthesmallballattheinstantshownasfigureare（）.

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****Twoidenticalhomogeneousdisksareplacedonasmoothhorizontalplane,andtwosamehorizontalforcesareappliedonthedifferentpositionsofthedisks,respectively,sothatthedisksstarttomovefromrest.ThemasscenterofdiskAmovesfaster.（）

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错WhenAparticleofmassmmovesinacircleataconstantspeedvA=vB=vfrompositionAtopositionB,theimpulseoftheforceactingontheparticleis（）.

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****Thefigureshowsacrank-rodmechanismontheplatform,whichiscomposedoftwohomogeneousbarsandaslider.TherodO1Arotatesatauniformangularvelocityωandgiven:O1AweighsP1,ABweighsP2,platformweighsQ,O1A=AB=L.Lett=0,angle=0,andthevelocityofplatformiszero.ExcludingthemassofthesliderBandthefrictionontheground,themotionalequationoftheplatformis（）.

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****A

homogeneousrodOArotatesaroundthefixedaxis

O

withconstantangularvelocity

ω.Themassoftherodis

m

anditslengthis

L,thenthemagnitudeofmomentumofthisrodis

mLω/2.

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对第十二章测试AhomogeneousrodOAwithmassmandlengthLrotatesaroundthefixedaxisOatuniformangularspeedω,thenthemagnitudeofangularmomentumofthisrodtoaxisOis（）.

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mL2ω/3Thetriangleplaterotatesataconstantangularvelocit