More curriculum can be found in Pearson Addison Wesley‘s Conceptual Physics Laboratory Manual: Activities · Experiments · Demonstrations · Tech Labs by Paul G. Hewitt and Dean Baird. ISBN: 0321732480

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CONCEPTUAL PHYSICS: Hewitt/Baird Tech Lab

Linear Motion Motion Graphing Simulation

Motivating the Moving Man PurposeTostudyone‐dimensionalmotionthroughtheuseofacomputersimulationApparatuscomputerPhETsimulation:“MovingMan”(availableathttp://phet.colorado.edu)

Setup1.Turnthecomputeron,logonandallowittocompleteitsstartupcycle.

2.FindandstartthePhETSimulationsandruntheMovingMansimulation.Askyourinstructorforassistanceifneeded.

3.Locatethetime‐scaleexpansionbutton.Timeisthehorizontalaxis,nottheverticalaxis.Usethetime­scaleexpansionbuttontoexpandthetimeaxissothatonly10secondscanbeseen.

4.Findandusethebuttonsthatwilldeletethevelocityvs.timeandaccelerationvs.timegraphs.Youareleftwithonegraph:positionvs.time.Anditshorizontalaxisnowrunsfromonly0to10seconds.

5.SetthecomputerasideandreadtheDiscussionsectionbelow.WhenyouhavefinishedreadingtheDiscussion,continuewiththeactivity.

DiscussionThesimulationprovidesuswithasimpleinterfacewecanusetostudymotiongraphs.Specifically,wecancontroltheposition,velocity,andaccelerationofanobjectandseethegraphsofposition,velocity,andaccelerationofthatobject.

Thesimulationallowsustomanuallycontroltheobjectbydraggingit.Wecanalsodragaposition“slider”control.

Moreimportantly,wecansetinitialconditionsfortheobjectthenletitsmotionproceed.Wecanpausethemotion,andthemotionislimitedinspacebythewalls.

ProcedureStep1:Completethematchingexerciseonthenextpage.Thenamesofmanyobjectsandbuttonsarelisted.Drawalineconnectingthenameofeachobjectorbuttontotheobjectorbutton,itself.YourscreenandFigure1shouldbeverysimilarinthatonlythepositionvs.timegraphisvisibleandthatthehorizontal(time)scalerunsfrom0to10seconds.PhETsimulationsarerevisedfromtimetotime,sosomeelementsofthescreenlayoutmayhavechanged.

Step2:ManualMana. Clickonthemananddraghiminthepositivedirection(towardthehouse)atasteadyrateof

1m/stothebestofyourability.Yourgraphwon’tbeperfect(limitationsofthecomputer’sinterfacepreventthis),buttrytomovethemanassmoothlyasyoucanat1m/s.

b. Whilethegraphisstillonthescreen,clicktheon‐screenbuttontoshowthevelocityvs.timegraph.Thisgraphplotsthevalueofthevelocityastimepasses.Clearthegraphsandtryagain.Movethemanmanuallyfrom0to10metersin10seconds—assmoothlyaspossible—at1m/s.Thesimulation’s“stopwatch”readingindicatestime.

More curriculum can be found in Pearson Addison Wesley‘s Conceptual Physics Laboratory Manual: Activities · Experiments · Demonstrations · Tech Labs by Paul G. Hewitt and Dean Baird. ISBN: 0321732480

More curriculum can be found in Pearson Addison Wesley‘s Conceptual Physics Laboratory Manual: Activities · Experiments · Demonstrations · Tech Labs by Paul G. Hewitt and Dean Baird. ISBN: 0321732480

c. Sketchtheresultingpositionvs.timeandvelocityvs.timegraphsonthegraphspageattheendofthiswrite‐up.

Step3:ProgrammedMana. Makesurethepositionandvelocitygraphsareshowing(withthetimescalesetfrom0to10

seconds)andtheaccelerationgraphishidden(deleted).Clearthegraphs.

b. Settheinitialpositionofthemanto0m.(Usethesliderortypeitintothevaluebox.)

c. Settheinitialvelocityofthemanto+1.0m/s.(Usethesliderortypeitintothevaluebox.)

d. Clickanon‐screenGobuttonandobservetheresultingmotiongraphs.Sketchbothgraphs(positionvs.timeandvelocityvs.time)onthegraphspageattheendofthelab.

e. Clearthegraphs.Settheinitialvelocityofthemanto+2.0m/sandrunthesimulationagain.Themotionendswhenthemanhitsthewall.Stopthesimulationwhenthatoccurs.Disregarddatafromthewallimpactandbeyond.Describetwodifferencesinthepositionvs.timegraph.(Hints:rise/run;duration.)

f. Addlinestoyourprevioussketchrepresentingthe+2.0m/smotion.Besuretolabelbothlinesnowplotted.Anddonotincludeplotteddataaftertheimpactwiththewall.

g. Addandlabeladashedlinetothegraphsshowingtheresultiftheinitialvelocityofthemanwere+5m/s.(Note:donotcarrythisprocedureoutonthesimulation.)

h. Describetwochangesthatoccuronthevelocityvs.timegrapheachtimeyoumaketheinitialspeedofthemangreater.

Step4:BackUptheChoo­Chooa. Clearthegraphs.Theaccelerationgraphisstillhidden.

b. Settheinitialpositionofthemanto0m.Settheinitialvelocityofthemanto–2.0m/s.

c. Runthesimulationandobservethemotiongraphs.Again,themotionendswhenMovingMancrashesintothewall,sostopthesimulationwhenthathappens.SketchthegraphsonthesamesetofaxesusedforStep3,disregardingdatafromthewallimpactandbeyond.

d. Clearthegraphs.Settheinitialvelocityofthemanto–4.0m/sandrunthesimulation.Describetwodifferencesinthepositionvs.timegraph,andaddalinetoyourprevioussketchrepresentingthe–4.0m/smotion.Besuretolabelbothlinesnowplotted.

e. Addandlabeladashedlinetothegraphsshowingtheresultiftheinitialvelocityofthemanwere–10m/s.(Note:Donotcarrythisprocedureoutinthesimulation.)

More curriculum can be found in Pearson Addison Wesley‘s Conceptual Physics Laboratory Manual: Activities · Experiments · Demonstrations · Tech Labs by Paul G. Hewitt and Dean Baird. ISBN: 0321732480

f. Describetwochangesthatoccuronthevelocityvs.timegrapheachtimeyoumaketheinitialspeedofthemangreater(fasterinthenegativedirection).

g. Clicktheon‐screenbuttontoshowtheaccelerationvs.timegraph.Whatdoestheaccelerationvs.timegraphtellyouaboutthemotionsobservedsofar?

Step5:Pickin’UpthePace

a. Clearthegraphs.Allthreegraphsarenowshowing.

b. Settheinitialpositionofthemanto0m.Settheinitialvelocityofthemanto0m/s.Settheaccelerationofthemanto+0.5m/s2.

c. Runthesimulationandobservethemotiongraphs.Sketchthegraphsonthegraphpage.

d. Whatdoestheaccelerationvs.timegraphtellyouaboutthenatureofthismotion?(Donotrefertonumericalvaluesinyourresponse.)

Step6:OnceMore,WithFeelinga. Settheinitialpositionofthemanto0m.Settheinitialvelocityofthemanto0m/s.Setthe

accelerationtothemanto+2.0m/s2.

b. Runthesimulationandobservethepositionvs.timegraph.

i. Sketchthegraphonthesamesetofaxesaspart5.

ii. Howisthispositionvs.timegraphdifferentfromtheoneplottedinpart5above?

c.Howdoesthevelocityvs.timegraphdifferfromtheoneproducedinpart5above?

d.BasedonwhatyoulearnedinSteps5and6,sketchallthreemotiongraphsthatthemanwouldproduceifhestartedatx=0m,v=0m/s,anda=–1m/s2.Don’tactuallycarrythisprocedureoutonthesimulation.Simplysketchwhatyouthinkitshouldbebasedonyourexperience.

More curriculum can be found in Pearson Addison Wesley‘s Conceptual Physics Laboratory Manual: Activities · Experiments · Demonstrations · Tech Labs by Paul G. Hewitt and Dean Baird. ISBN: 0321732480

Step7:RoundTripa. Withallthreegraphsshowing,adjustthescaleofthetimeaxistodisplay20seconds.

b. Settheinitialpositionofthemanto–10m.Settheinitialvelocityto+3.0m/s.Settheaccelerationto–0.3m/s2.

c. Runthesimulationandobservethemotiongraphs.Sketchthegraphsonthegraphspage.

d. Selectthebestdescriptionsofthevelocityandaccelerationofthemanattheapexofhismotion(whenhe’sisfarthestfromhisstartingpoint).Chooseonedescriptionoftheman’svelocityandonedescriptionoftheman’sacceleration.Feelfreetousetherewindandforwardstepfeaturesofthesimulation.

__The velocity is positive: the man is moving to the right. __The velocity is zero: the man is at rest. __The velocity is negative: the man is moving to the left.

__The acceleration is positive: the man’s velocity is increasing. __The acceleration is zero: the man is maintaining constant velocity. __The acceleration is negative: the man’s velocity is decreasing.

e. Youoverhearaclassmatetellingsomeonethatit’spossibleforanobjecttobeatrestandacceleratingatthesametime.Whatdoyouthinkofthatstatement?

Step8:TheSloshingManPuzzlea. Clearallgraphs.Setthepositionnear–2m.Clickanddragthemanfrom–2mto+2mwith

uniformmotionandlethimrest.Thendraghimfrom+2mto–2mwithuniformmotionandlethimrest.Repeat.Theresultingpositionvs.timegraphshouldlooksimilartotheplotbelow.Don’tworryaboutthetimetoomuch;what’simportantismovingthemanoneway,thenresting,thenmovinghimtheotherway,thenresting.Yourlineswon’tbeasstraight,andthe“corners”ofyourgraphwillberounderthanthosedepictedbelow.

b. Examinethesectionoftheplotenclosedinthedashedbox.Thevelocityvs.timegraphhasapatternsimilartotheoneshownbelow.Unlikethetime‐alignedgraphsinthesimulation,thisgraphmayhavebeenshiftedhorizontally.Drawaboxtoenclosethesectionofthevelocitygraphthatcorrespondstotheboxedsectionofthepositionvs.timegraphabove.

Figure 2. Ideal Position vs. Time for Sloshing Man

Figure 3. Ideal Velocity vs. Time Segment for Sloshing Man

More curriculum can be found in Pearson Addison Wesley‘s Conceptual Physics Laboratory Manual: Activities · Experiments · Demonstrations · Tech Labs by Paul G. Hewitt and Dean Baird. ISBN: 0321732480

c. Theaccelerationvs.timegraphhasapatternsimilartotheoneshownbelow.Again,thisgraphmayhavebeenshiftedalongthetimeaxis.Anditisnotnecessarilytoscale.Drawaboxtoenclosethesectionoftheaccelerationgraphthatcorrespondstotheboxedsectionofthepositionvs.timegraphabove.

d. SketchthevelocityandaccelerationplotsinthespacebelowthepositionplotinFigure5below.

e. MatchthephrasesbelowtothemotionillustratedinFigure5.UsepointsA,B,C,orD,orsegments(e.g.,AB,BD).

Sustained positive velocity _______ Sustained negative velocity _______ Rest _______

Positive acceleration to start motion _______ Positive acceleration to stop motion _______

Negative acceleration to start motion _______ Negative acceleration to stop motion _______

Figure 4. Ideal Acceleration vs. Time Segment for Sloshing Man

Figure 5. Motion Graph Segment for Sloshing Man

More curriculum can be found in Pearson Addison Wesley‘s Conceptual Physics Laboratory Manual: Activities · Experiments · Demonstrations · Tech Labs by Paul G. Hewitt and Dean Baird. ISBN: 0321732480

More curriculum can be found in Pearson Addison Wesley‘s Conceptual Physics Laboratory Manual: Activities · Experiments · Demonstrations · Tech Labs by Paul G. Hewitt and Dean Baird. ISBN: 0321732480