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第一章热力学基本概念英文习题1.ExpressingtemperatureriseindifferentunitsDuringaheatingprocess,thetemperatureofasystemrisesby10℃.ExpressthisriseintemperatureinK,℉andR.2.AbsolutepressureofavacuumchamberAvacuumgageconnectedtoachamberreads5.8psiatlocationwheretheatmospherepressureis14.5psi.Determinetheabsolutepressureinthechamber.3.MeasuringpressurewithamanometerAmanometerisusedtomeasurethepressureinatank.Thefluidusedhasaspecificgravityof0.85,andthemanometercolumnheightis55cm,asshowninFig.1-1.Ifthelocalatmosphericpressureis96kPa,determinetheabsolutepressurewithinthetank.4.Measuringpressurewithamulti-fluidmanometerThewaterinatankispressurizedbyair,andthepressureismeasuredbyamulti-fluidmanometerasshowninFig.1-2.Thetankislocatedonamountainatanaltitudeof1400mwheretheatmosphericpressureis85.6kPa.Determinetheairpressureinthetankifh1=0.1m,h2=0.2m,andh3=0.35m.Takethedensitiesofwater,oil,andmercurytobe1000kg/m3,850kg/m3,and13600kg/m3respectively.5.EffectofpistonweightonpressureinacylinderThepistonofaverticalpiston-cylinderdevicecontainingagashasamassof60kgandacross-sectionalareaof0.04m2,asshowninFig.1-3.Thelocalatmospherepressureis0.97bar,andthegravitationalaccelerationis9.81m/s2.(a)Determinethepressureinsidethecylinder.(b)Ifsomeheatistransferredtothegasanditsvolumeisdoubled,doyouexpectthepressureinsidethecylindertochange?6.BurningofflunchcaloriesA90-kgmanhadtwohamburgers,aregularservingofFrenchfries,anda200-mlCokeforlunch.Determinehowlongitwilltakeforhimtoburnthelunchcaloriesoff(a)bywatchingTVand(b)byfastswimming.Whatwouldyouranswersbefora45-kgman?7.BurningofacandleinaninsulatedroomAcandleisburninginawell-insulatedroom.Takingtheroom(theairplusthecandle)asthesystem,determine(a)ifthereisanyheattransferduringthisFIGURE1-1FIGURE1-1FIGURE1-2FIGURE1-2FIGURE1-3FIGURE1-3FIGURE1-4FIGURE1-4burningprocessand(b)ifthereisanychangeintheinternalenergyofthesystem.8.Boundaryworkduringaconstant-volumeprocessArigidtankcontainsairat500kPaand150℃.Asaresultofheattransfertothesurroundings,thetemperatureandpressureinsidethetankdropto65℃and400kPa,respectively.Determinetheboundaryworkdoneduringtheprocess.9.IsothermalcompressionofanidealgasApiston-cylinderdeviceinitiallycontains0.4m3ofairat100kPaand80℃.Theairisnowcompressedto0.1m3insuchawaythatthetemperatureinsidethecylinderremainsconstant.Determinetheworkdoneduringthisprocess.10.HeattransferfromapersonConsiderapersonstandinginabreezyroomat20℃.Determinethetotalrateofheattransferfromthispersoniftheexposedsurfaceareaandtheaverageoutersurfacetemperatureofthepersonare1.6m2and29℃,respectively,andtheconvectionheattransfercoefficientis6W/m2.℃(Fig.1-7)工程热力学与传热学第一章基本概念习题ExpressingtemperatureriseindifferentunitsDuringaheatingprocess,thetemperatureofasystemrisesby10℃.ExpressthisriseintemperatureinK,℉andR.2.AbsolutepressureofavacuumchamberAvacuumgageconnectedtoachamberreads5.8psiatlocationwheretheatmospherepressureis14.5psi.Determinetheabsolute习题FIGURE1-1FIGURE1-1FIGURE1-5FIGURE1-5FIGURE1-6FIGURE1-6FIGURE1-7FIGURE1-7pressureinthechamber.3.MeasuringpressurewithamanometerAmanometerisusedtomeasurethepressureinatank.Thefluidusedhasaspecificgravityof0.85,andthemanometercolumnheightis55cm,asshowninFig.1-1.Ifthelocalatmosphericpressureis96kPa,determinetheabsolutepressurewithinthetank.4.Measuringpressurewithamulti-fluidmanometerThewaterinatankispressurizedbyair,andthepressureismeasuredbyamulti-fluidmanometerasshowninFig.1-2.Thetankislocatedonamountainatanaltitudeof1400mwheretheatmosphericpressureis85.6kPa.Determinetheairpressureinthetankifh1=0.1m,h2=0.2m,andh3=0.35m.Takethedensitiesofwater,oil,andmercurytobe1000kg/m3,850kg/m3,and13600kg/m3respectively.5.EffectofpistonweightonpressureinacylinderThepistonofaverticalpiston-cylinderdevicecontainingagashasamassof60kgandacross-sectionalareaof0.04m2,asshowninFig.1-3.Thelocalatmospherepressureis0.97bar,andthegravitationalaccelerationis9.81m/s2.(a)Determinethepressureinsidethecylinder.(b)Ifsomeheatistransferredtothegasanditsvolumeisdoubled,doyouexpectthepressureinsidethecylindertochange?6.BurningofflunchcaloriesA90-kgmanhadtwohamburgers,aregularservingofFrenchfries,anda200-mlCokeforlunch.Determinehowlongitwilltakeforhimtoburnthelunchcaloriesoff(a)bywatchingTVand(b)byfastswimming.Whatwouldyouranswersbefora45-kgman?7.BurningofacandleinaninsulatedroomAcandleisburninginawell-insulatedroom.Takingtheroom(theairplusthecandle)asthesystem,determine(a)ifthereisanyheattransferduringthisburningprocessand(b)ifthereisanychangeintheinternalenergyofthesystem.8.Boundaryworkduringaconstant-volumeprocessArigidtankcontainsairat500kPaand150℃.Asaresultofheattransfertothesurroundings,thetemperatureandpressureinsidethetankdropto65℃and400kPa,respectively.Determinetheboundaryworkdoneduringtheprocess.FIGURE1-2FIGURE1-2FIGURE1-3FIGURE1-3FIGURE1-4FIGURE1-4FIGURE1-5FIGURE1-5FIGURE1-6FIGURE1-69.IsothermalcompressionofanidealgasApiston-cylinderdeviceinitiallycontains0.4m3ofairat100kPaand80℃.Theairisnowcompressedto0.1m3insuchawaythatthetemperatureinsidethecylinderremainsconstant.Determinetheworkdoneduringthisprocess.10.H