机械工程专业英语课件--L01

EnglishforMechanicalEngineering机械工程专业英语常州工学院机电工程学院徐红丽机械工程专业英语预备知识一、BackgroundInformationCHAPTER1MATERIALSANDHOTWORKLesson1BasicConceptsinMechanicsInrationalmechanics,mechanicalworkistheamountofenergytransferredbyaforceactingthroughadistance.Likeenergy,itisascalarquantity,withSIunitsofjoules.Thetermworkwasfirstcoinedinthe1830sbytheFrenchmathematicianGaspard-GustaveCoriolis.Themechanicalworkappliedtoanobjectcanbecalculatedfromthedotproductoftheappliedforce(F)andthedisplacement(d)oftheobject.Work：InternationalSystemofUnits(SI)机械工程专业英语一、BackgroundInformationLesson1BasicConceptsinMechanicsAbaseballpitcherdoespositiveworkontheballbytransferringenergyintoit.预备知识机械工程专业英语一、BackgroundInformationLesson1BasicConceptsinMechanicsEfficiencyMechanicalEfficiencyistheratioofworkinputtoworkoutput.Itisoftenexpressedasapercentage.Theefficiencyofanidealmachineis100%butanactualmachine'sefficiencywillalwaysbelessthan100%becauseoftheSecondlawofthermodynamicswhichstatesthatthequalityofenergywilldecay,eventuallybecomingheat.Thismeansthatsomeoftheworkputintothesystemistransformed(lost)intothermalenergy(heat).Inamechanicalsystem,frictionisthemostcommoncauseoftheworklosttoheat.预备知识机械工程专业英语一、BackgroundInformationLesson1BasicConceptsinMechanicsMechanicalAdvantageInphysicsandengineering,mechanicaladvantage(MA)isthefactorbywhichamechanismmultipliestheforceortorqueputintoit.Generally,themechanicaladvantageiscalculatedasfollows:ormoresimply:预备知识MechanicalAdvantage：机械工程专业英语Lesson1BasicConceptsinMechanics预备知识MechanicalAdvantage：机械工程专业英语Lesson1BasicConceptsinMechanics预备知识机械工程专业英语词汇Lesson1BasicConceptsinMechanics二、WordsandExpressionsmechanics[mi’kæniks]n.机械学，力学.abbr.mech.modify[‘mCdifai]v.修改，调解，变更manageable[5mAidVEbl]adj.可控制的、易处理的、便于管理的incline[in5klain]vt.（使）倾斜vi.倾斜，倾向n.倾斜，斜坡，斜面ramp[rAmp]n.斜板,斜坡,敲诈vi.狂跳乱撞,敲诈,蔓延vt.使有斜面,敲诈slope[slEup]n.斜坡,斜面,倾斜v.(使)顺斜rampslope斜坡坡度机械工程专业英语Lesson1BasicConceptsinMechanics二、wordsandExpressionsfriction[5frikFE]n.摩擦,摩擦力roll[5rEul]vt.滚动,滚转,(使)摇摆,(使)摇晃,卷起,卷拢,辗,轧n.卷,卷形物,摇晃,摆动,名单multiplier[5mQltiplaiE]n.放大器，乘法broom[bru:m]n.扫帚[植]金雀花vt.扫除broomcorn高粱broomrape肉苁蓉Anewbroomsweepsclean新官上任三把火convert[k[5vE:t]n.皈依者vt.使转变,转换...,使...改变信仰handle[5hAdl]n.手柄vt.触摸,运用,买卖,处理,操作n.[计]句柄词汇机械工程专业英语Lesson1BasicConceptsinMechanics二、wordsandExpressionssweep[swi:p]v.清扫,席卷,掠过，斜坡，斜面efficiency[i5fiFEsi]n.效率，功效efficientadj.efficientlyadv.gauge[geIdV]v.测量，校验n.标准尺,规格,量规,量表bearing[5bZEriN]n.轴承,关系,方面,意义,方向idealmechanicaladvatage[[d5va:tidV]理想的机械效益neglect[i5glekt]vt.忽略，忽视n.neglectofduty疏于职守negligible[5eglidVEbl]adj.可以忽略的，不予重视的词汇Workisdefinedasforcemultipliedbythedistanceoverwhichtheforceacts.Workismeasuredinmetre-kilograms.Ametre-kilogramequalstheworkdonebyaforceofonekilogramactingthroughadistanceofonemetre.Forexample,ifaworktaskinvolvesliftinga300kilogrammachinetwoandonehalfmetresintoatruck,then750metrekilogramsofworkisrequired.Sincenohumanscanlift300kilogramsdirectly,adevicemustbeemployedtomodifytherequiredeffortintosomethingmanageable.机械工程专业英语Lesson1BasicConceptsinMechanics课文分析机械工程专业英语Workisdefinedasforcemultipliedbythedistanceoverwhichtheforceacts.Workismeasuredinmetre-kilograms.功的定义是力乘以沿力的作用方向物体移动的距离。功的单位用公斤·米来表示。Lesson1BasicConceptsinMechanicsAmetre-kilogramequalstheworkdonebyaforceofonekilogramactingthroughadistanceofonemetre.l公斤·米等于1公斤力作用于物体上使物体移动l米的距离所作的功。课文分析机械工程专业英语Forexample,ifaworktaskinvolvesliftinga300kilogrammachinetwoandonehalfmetresintoatruck,then750metrekilogramsofworkisrequired.例如，一项任务需要将一台300公斤重的设备提升到2.5米高的卡车上，那么就需要做750公斤·米的功。Sincenohumanscanlift300kilogramsdirectly,adevicemustbeemployedtomodifytherequiredeffortintosomethingmanageable.Lesson1BasicConceptsinMechanics课文分析由于没有人能直接举起300公斤的重物，因此必须使用一种设备将所需的作用力转变成人力所能及的。机械工程专业英语Onecommondeviceisaninclinedplane---inthiscase,aloadingrampthatslopesfromthegroundtothetruck,Iftherampwere10metreslongandfrictionforceswerenegligiblysmall,then75kilogramsofforcewouldberequiredtorollthemachineuptheramp.Thetotalworkisstill750metre-kilograms(10metresmultipliedby75kilograms),buttheefforthasbeenmodifiedsothatthemaximumforcerequiredisonly75kilograms.Lesson1BasicConceptsinMechanics课文分析机械工程专业英语Onecommondeviceisaninclinedplane---inthiscase,aloadingrampthatslopesfromthegroundtothetruck,Iftherampwere10metreslongandfrictionforceswerenegligiblysmall,then75kilogramsofforcewouldberequiredtorollthemachineuptheramp.Lesson1BasicConceptsinMechanics[’neglidʒəbl]adj.可以忽略的;无足轻重的;课文分析常用的装置是一个斜面---在这个例子中，一个倾斜在地面和卡车之间的承载斜板，如果斜板有10米长，摩擦力很小可忽略不计的话，那么就只需要75公斤的力将机器滚上斜板。机械工程专业英语Thetotalworkisstill750metre-kilograms(10metresmultipliedby75kilograms),buttheefforthasbeenmodifiedsothatthemaximumforcerequiredisonly75kilograms.Lesson1BasicConceptsinMechanics总功仍然是750公斤·米(用75公斤乘以10米)，但作用力已经被改变，于是其所需的最大外力仅仅是75公斤。课文分析Adevicethatdecreasesthenecessaryappliedforcewhileincreasingthedistanceoverwhichthesmallerforceactsiscalledaforcemultiplier.Machinescanalsomultiplyspeedanddistance.Abroomisanexampleofaspeedanddistancemultiplierbecauseitconvertsinputforceanddistanceatthehandleintoalowerforceandlargerdistanceatthesweepingend.Sincethelarge