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1、146-152CH06-S1-8458133/21/049:17PMPage146WhatYou’llLearn•YouwilluseNewton’slawsandyourknowledgeofvectorstoanalyzemotionintwodimensions.•Youwillsolveproblemsdealingwithprojectileandcircularmotion.•Youwillsolverelative-velocityproblems.WhyIt’sImportant
2、Almostalltypesoftransportationandamusement-parkattractionscontainatleastoneelementofprojectileorcircularmotionorareaffectedbyrelativevelocities.SwingingAroundBeforethisridestartstomove,theseatshangstraightdownfromtheirsupports.Whentheridespeedsup,the
3、seatsswingoutatanangle.ThinkAboutThisWhentheswingsaremovingaroundthecircleataconstantspeed,aretheyaccelerating?physicspp.com146GibsonStockPhotography146-152CH06-S1-8458133/21/049:19PMPage147Howcanthemotionofaprojectilebedescribed?QuestionCanyoudescr
4、ibeaprojectile’smotioninboththehorizontalandtheverticaldirections?ProcedureCriticalThinkingDescribethemotionofahorizontallylaunchedprojectile.1.Withamarkedgridinthebackground,videotapeaballthatislaunchedwithaninitialvelocityonlyinthehorizontaldirecti
5、on.2.MakeandUseGraphsOnasheetofgraphpaper,drawthelocationoftheballevery0.1s(3frames).3.Drawtwomotiondiagrams:onefortheball’shorizontalmotionandoneforitsverticalmotion.AnalysisHowdoestheverticalmotionchangeastimepasses?Doesitincrease,decrease,orstayth
6、esame?Howdoesthehorizontalmotionchangeastimepasses?Doesitincrease,decrease,orstaythesame?6.1ProjectileMotionfyouobservedthemovementofagolfballbeinghitfromatee,afrogIObjectiveshopping,orafreethrowbeingshotwithabasketball,youwould•Recognizethatthevert
7、icalnoticethatalloftheseobjectsmovethroughtheairalongsimilarpaths,andhorizontalmotionsofaasdobaseballs,arrows,andbullets.Eachpathisacurvethatmovesprojectileareindependent.upwardforadistance,andthen,afteratime,turnsandmovesdownward•Relatetheheight,tim
8、eintheair,andinitialverticalforsomedistance.Youmaybefamiliarwiththiscurve,calledaparabola,velocityofaprojectileusingfrommathclass.itsverticalmotion,andAnobjectshotthroughtheairiscalledaprojectile.Aprojectilecanbethendeterminetherangeafootball,abullet
