In this lab you will begin to use conservation of energy toWord格式文档下载.docx
- 文档编号:19784043
- 上传时间:2023-01-10
- 格式:DOCX
- 页数:17
- 大小:56.16KB
In this lab you will begin to use conservation of energy toWord格式文档下载.docx
《In this lab you will begin to use conservation of energy toWord格式文档下载.docx》由会员分享,可在线阅读,更多相关《In this lab you will begin to use conservation of energy toWord格式文档下载.docx(17页珍藏版)》请在冰豆网上搜索。
Objectives:
Successfullycompletingthislaboratoryshouldenableyouto:
•Useconservationofenergytopredicttheoutcomeofinteractionsbetweenobjects.
•Chooseausefulsystemwhenusingconservationofenergy.
•Identifydifferenttypesofenergywhenapplyingenergyconservationtorealsystems.
•Decidewhenconservationofenergyisnotusefultopredicttheoutcomeofinteractionsbetweenobjects.
Preparation:
ReadPaulM.Fishbane:
Chapter6,Chapter7.Youshouldalsobeableto:
•Analyzethemotionofanobjectusingvideoanalysis.
•Calculatethekineticenergyofamovingobject.
•Calculatetheworktransferredtoorfromasystembyanexternalforce.
•Calculatethetotalenergyofasystemofobjects.
•Calculatethegravitationalpotentialenergyofanobjectwithrespecttotheearth.
Problem#1:
kineticenergyandworki
Youareworkingatacompanythatdesignspinballmachinesandhavebeenaskedtodeviseatesttodeterminetheefficiencyofsomenewmagneticbumpers.Youknowthatwhenanormalpinballreboundsofftraditionalbumpers,someoftheinitialenergyofmotionis"
inthedeformationoftheballandbumper,thusslowingtheballdown.Theleadengineerontheprojectassignsyoutodetermineifthenewmagneticbumpersaremoreefficient.Theengineertellsyouthattheefficiencyofacollisionistheratioofthefinalkineticenergytotheinitialkineticenergyofthesystem.
Tolimitthemotiontoonedimension,youdecidetomodelthesituationusingacartwithamagnetcollidingwithamagneticbumper.Youwillusealeveltrack,anduseavideodataacquisitionsystemtomeasurethecart’svelocitybeforeandafterthecollision.Youbegintogatheryourcameraanddataacquisitionsystemwhenyourcolleaguesuggestsamethodwithsimplerequipment.Yourcolleagueclaimsitwouldbepossibletoreleasethecartfromrestonaninclinedtrackandmakemeasurementswithjustameterstick.Youarenotsureyoubelieveit,soyoudecidetomeasuretheenergyefficiencybothways,anddeterminetheextenttowhichyougetconsistentresults.Forthisproblem,youwillusetheleveltrack.Forproblem#2,youwillworkwiththeinclinedtrack.
Equipment
Youwillusethevideoanalysisequipmenttoanalyzethemotionofacartcollidingwithanendstop(themagneticbumper)onthetrack.Youwillalsohaveameterstick,astopwatchandabalancetomeasurethemassofthecart.
Predictions
Calculatetheenergyefficiencyofthebumperdiscussedintheproblemintermsoftheleastnumberofquantitiesthatyoucaneasilymeasureinthesituationofaleveltrack.Calculatetheenergydissipatedduringtheimpactwiththebumperintermsofthosemeasurablequantities.
Warmup
Read:
FishbaneChapter6,section6.1.
1.Itisusefultohaveanorganizedproblem-solvingstrategy.Thefollowingquestionswillhelpwithyourpredictionandtheanalysisofyourdata.
2.Makeadrawingofthecartontheleveltrackbeforeandaftertheimpactwiththebumper.Defineyoursystem.Labelthevelocityandkineticenergyofallobjectsinyoursystembeforeandaftertheimpact.
3.Writeanexpressionfortheefficiencyofthebumperintermsofthefinalandinitialkineticenergyofthecart.
4.Writeanexpressionfortheenergydissipatedduringtheimpactwiththebumperintermsofthekineticenergybeforetheimpactandthekineticenergyaftertheimpact.
Exploration
Reviewyourexplorationnotesformeasuringavelocityusingvideoanalysis.Practicepushingthecartwithdifferentvelocities,slowlyenoughthatthecartwillnevercontactthebumper(endstop)duringtheimpactwhenyoumakeameasurement.Findarangeofvelocitiesforyourmeasurement.Setupthecameraandtripodtogiveyouausefulvideoofthecollisionimmediatelybeforeandafterthecartcollideswiththebumper.
Althoughtheeffectoffrictionissmallinourlab,youmaywanttoestimateit.Makeascheduletotesttheeffectoffrictionbythedatafromvideo.
Measurement
Takethemeasurementsnecessarytodeterminethekineticenergybeforeandaftertheimpactwiththebumper.Whatisthemostefficientwaytomeasurethevelocitieswiththevideoequipment?
Takedataforseveraldifferentinitialvelocities.
Analysis
Calculatetheefficiencyofthebumperfortheleveltrack.Doesyourresultdependonthevelocityofthecartbeforeithitsthebumper?
Conclusion
Whatistheefficiencyofthemagneticbumpers?
Howmuchenergyisdissipatedinanimpact?
Whatiseffectoffrictioninyourexperiment?
Stateyourresultsinthemostgeneraltermssupportedbyyouranalysis.
Ifavailable,compareyourvalueoftheefficiency(withuncertainty)withthevalueobtainedbythedifferentproceduregiveninthenextproblem.Arethevaluesconsistent?
Whichwaytomeasuretheefficiencyofthemagneticbumperdoyouthinkisbetter?
Why?
problem#2:
kineticenergyandworkii
Tolimitthemotiontoonedimension,youdecidetomodelthesituationusingacartwithamagnetcollidingwithamagneticbumper.Youwillusealeveltrack,anduseavideodataacquisitionsystemtomeasurethecart’svelocitybeforeandafterthecollision.Youbegintogatheryourcameraanddataacquisitionsystemwhenyourcolleaguesuggestsamethodwithsimplerequipment.Yourcolleagueclaimsitwouldbepossibletoreleasethecartfromrestonaninclinedtrackandmakemeasurementswithjustameterstick.Youarenotsureyoubelieveit,soyoudecidetomeasuretheenergyefficiencybothways,anddeterminetheextenttowhichyougetconsistentresults.Forthisproblem,youwillusetheinclinedtrack.Forproblem#1,youwillworkwiththeleveltrack.
Youwillhaveameterstick,astopwatch,cartmassesandawoodenblocktocreatetheincline.Youmayalsousethevideoanalysisequipmenttoestimatetheeffectoffriction.
Calculatetheenergyefficiencyofthebumper(withfrictionandwithout)intermsoftheleastnumberofquantitiesthatyoucaneasilymeasureinthesituationofaninclinedtrack.
FishbaneChapter6,sections6.1-6.2.
Thefollowingquestionswillhelpyoutomakeyourpredictionandanalyzeyourdata.
1.Makeadrawingofthecartontheinclinedtrackatitsinitialposition(beforeyoureleasethecart)andjustbeforethecarthitsthebumper.Definethesystem.Labelthekineticenergyofallobjectsinyoursystematthesetwopoints,thedistancethecarttraveled,theangleofincline,andtheinitialheightofthecartabovethebumper.
2.Nowmakeanotherdrawingofthecartontheinclinedtrackjustafterthecollisionwiththebumperandatitsmaximumreboundheight.Labelkineticenergyofthecartatthesetwopoints,thedistancethecarttraveled,theangleoftheramp,andthereboundheightofthecartabovethebumper.
3.Writeanexpressionfortheefficiencyofthebumperintermsofthekineticenergyofthecartjustbeforetheimpactandthekineticenergyofthecartjustaftertheimpact.
4.Drawaforcediagramofthecartasitmovesdownthetrack.Whichforcecomponentdoesworkonthecart(i.e.,causesatransferofenergyintothecartsystem)?
Writeanexpressionfortheworkdoneonthecart.Howistheangleoftheramprelatedtothedistancethecarttraveledandtheinitialheightofthecartabovethebumper?
Howdoesthekineticenergyofthecartjustbeforeimpactcomparewiththeworkdoneonthecart?
5.Drawaforcediagramofthecartasitmovesupthetrack.Whichforcecomponentdoesworkonthecart(i.e.,causesatransferofenergyoutofthecartsystem)?
Writeanexpressionfortheworkdoneonthecart.Howdoesthekineticenergyofthecartjustafterimpactcomparewiththeworkdoneonthecart?
6.Writeanexpressionfortheefficiencyofthebumperintermsofthecart’sinitialheightabovethebumperandthecart’smaximumreboundheightabovethebumper.
7.Writeanexpressionfortheenergydissipatedduringtheimpactwiththebumperintermsofthekineticenerg
- 配套讲稿:
如PPT文件的首页显示word图标,表示该PPT已包含配套word讲稿。双击word图标可打开word文档。
- 特殊限制:
部分文档作品中含有的国旗、国徽等图片,仅作为作品整体效果示例展示,禁止商用。设计者仅对作品中独创性部分享有著作权。
- 关 键 词:
- In this lab you will begin to use conservation of energy
链接地址:https://www.bdocx.com/doc/19784043.html