Workshop 7 handout PDF

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Workshop 7 handout...

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Melbourne School of Engineering Engineering Systems Design 2 Workshop Seven (W07) SpringSystems&ResultantForce

Welcome to Workshop 7 for Engineering Systems Design 2. In this workshop, you will be performing Hooke’s Law experiment to obtain the characteristics of a spring and then utilize the springinaspringscalessystemtodeterminetheunknownmassofanobjectusingresultantforces. Successfulcompletionofallassessmenttasksinthisworkshopisworth1%ofyourfinalmarkinthe subject. 

Part A (General) ThequestionsfromtheESD2problembookletcoveredinthisworkshopare61,65,66,68,71,72, and73.

Part B (Hands-On Activity) There will be 2 parts to the experiment, first the Hooke’s Law experiment to determine the characteristicsofaspring,followedbytheexperimentonaspringscalessystemutilizingthespring todeterminetheunknownmassofanobject. Intheonlinedeliverymode,youwilluseaMATLABsimulationapp(withinMyUniApps)toperform theexperimentinsteadoftheactualhands‐on.  RunningtheMATLABsimulationapp 1.

Log in to MyUniApps. You may choose to do it via the Citrix Workspace App or via a web browser,http://myuniapps.unimelb.edu.au/

2.

UndertheDESKTOPStab,launchtheStudentDesktopMSE.

3.

FromwithintheMSEStudentDesktop,openCanvasanddownloadtheWorkshop_7.exefile. Openthefolderthatthefilewasdownloadedinto(likelytheDocuments‐>Downloads)and doubleclicktorunit.Theappwilltakeawhiletoload.[theWorkshop_7.exefilewillrunfrom theMATLABRuntimeenvironment(Ver9.7Windows64‐bit)intheMyUniAppsserver]. Note:ThefilecanonlyberunfromtheDocumentsorDownloadsfolderthatitwasdirectly downloadedinto.Youcannotcopytheexefilefromortoanyotherfolder,itwillnotrundue topermissionissues.

4.

Oncesuccessful,thedefaultsimulationinterfaceinFigure1willload,wheretheHooke’sLaw experimenttabisactive.

 Figure1:Workshop7simulationapp  Important:Donot atanytimeclosethe appbeforeyouhavefinished alltheexperiments inthis workshop.ItisvitalthatyoucarryoutboththeHooke’sLawandspringscalesexperimentswithina singleinstanceofopeningthesimulationapp. In the Zoom workshop setting, only 1 member of the group should run the experiment (1 app instance) andshare their screen with the othermembers. Results should not be recorded across twoormoreappinstances.

 



Assessmenttasks(1%)  Hooke’sLawexperiment 1.

MeasuretherestlengthofthespringbytogglingtherulerON.[Note:thereadingsontheruler aregiveninmm,e.g.areadingof30ontherulermeans30mm3cm]

2.

Select the 500g mass from the dropdown menu and click Run to apply the mass onto the spring.

3.

RecordtheresultsinTable1. Experimentvalues Calculatedvalues Massappliedto Readingonrulerafter Forceappliedto Springextension, spring(g) massisapplied(cm) spring,F(N) x(m) 500            Table1:ResultsforHooke’sLawexperiment

4.

Increasetheloadonthespringbyselectingthenextmassvalue(e.g.550g).HittheRunbutton andrecordtherespectiveextension.

5.

Repeatstep4usingtherestofthemassvalues.

6.

UsingMATLAB,plotanF‐xgraphfromthedatainTable1(theextensionofthespringonthe horizontal axis, and the force on the vertical axis) using blue circles. Remember to label the axes.

7.

Toobtainthelineofbestfit,gototheToolsmenuofthefigureandselectBasicFitting.Select thelinearandShowequationsoptionstoobtaintheequationofthebestfitline,asshownin Figure2.

Figure2:Basicfittingtool 8.

Equatetheslopeandy‐intersectofthelinetothespringcharacteristics𝑘and𝑐.



SpringScalesexperiment 

[Note:youshouldNOThaveclosedtheappaftertheHooke’sLawexperimentbeforeproceedingto the Spring Scales experiment. If you have accidently closed the app, you will need to redo the Hooke’sLawexperiment] 

9.

SelecttheSpringScalesExperimenttabofthesimulationapp.

 Figure3:SpringScalesexperiment Theset‐upissuchthatthespring(fromtheprevioustab’sHooke’sLawexperiment)isattached perpendiculartothearmandthedistancebetweenthecenterofmassoftheunknownmass andthepointwherethespringforceisactingareequal(atadistanceof19cmfromthecenter beam). 10. InputthevaluesofkandcfromtheHooke’sLawexperimentintheyellowboxes. 11. Selecttheunknownmassobjectthatyouwishtouse,eitherA,BorC.[Youonlyneedtouse1 fortheassessment]. 12. SelectadditionalmassfromthedropdownmenustobalancethespringscalesandhittheRun

button.Balanceisindicatedbythecenteredpositionoftheredgaugeneedle. 13. ToggletherulerONtomeasuretheextensionofthespringwhenthescaleisbalanced. 14. WriteacodeinMATLABtocalculatethemassofyourselectedobjectintheunitofgrams. Hint:theforceappliedbythespringisequaltothetotalforceappliedbytheunknownmass andappliedmasssinceallforcesactingperpendicularlytothebalancedarm,andatanequal distancefromthecenterofthebalancebeam.  TheWorkshop7Assessmenttasksneedtobecompletedwithinyourworkshopclass,tobeverified byyourtutorbeforetheendofclass. Workshop7Assessment

Mark

Springcharacteristics,𝑘and𝑐,fromHooke’sLawexperiment

0.5%

Massofselectedobject(eitherA,BorC)

0.5%

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