Table of Contents -...

ScienceTutor:PhysicalScience

ii©MarkTwainMedia,Inc.,Publishers

Table of Contents

ii TableofContents

1 Introduction/HowtoUseThisBook

2 AUniverseofMotion,Forces,and

Energy

Part 1: Measuring Tools

3 MeettheMetricSystem

4 MeasuringWithMetrics

Part 2: The Mechanics of Motion

5 MeasuringSpeedandvelocity

7 GetReady,GetSet,Accelerate!

8 ConservingMotherMo(mentum)

9 AFeelingforForces

10 Newton’sBig3

11 FreeFa-a-allandGravity

12 ForcesinFluids

13 WorkandPower

14 Machines

15 PuttingItAllTogether

Part 3: All About Energy

16 Energy,letMeCountItsForms

17 KineticEnergy:TheEnergyofMotion

18 PotentialEnergy:TheEnergyofPosition

19 EnergyConversions

20 MovingHeatAround:Thermodynamics

21 ConserveEnergy—That’sthelaw!

22 ThelawsofThermodynamics

23 Entropy:AMeasureofDisorder


Part 4: Electricity and Magnetism

25 Force,Charge,andAtomicStructure

26 ElectricForcesandFields

27 MagnetsandMagneticInduction

28 MagneticFields

29 Forces,ElectricCurrents,andMagnetic

Fields

30 linkingMovingChargesandChanging

MagneticFields

31 EMFsandCircuits

32 Ohm’slawandResistance

33 PowerProductionandTransformers


Part 5: Waves of Light and Sound

35 WavesandTheirProperties

36 TypesandSpeedsofWaves

37 WaveInteractions

38 SoundandItsProperties

39 MixingSoundWaves

40 UsingSound

41 ElectromagneticWaves

42 TheElectromagnetic(em)Spectrum

43 visiblelight:A“Wavicle”


45 AnswerKeys

TableofContents


1©MarkTwainMedia,Inc.,Publishers

Introduction/How to Use This Book

Physical Scienceexplorestheuniverseofmotion,forces,andenergythatswirlsaboutusdailybutissometimestakenforgranted.Sincethemetricsystemiscrucialtoallscientificmeasurements,abrief introductionandreview isprovided inPart1:MeasuringTools,beforelaunchingintothemechanicsofmotionandforcesinPart2.Ametricruleisprintedonpage3,butyoumaywanttoprovideyourownrulersandmetricmeasuresforsomeactivities.Part3 examines energy in all its forms, and discusses energy conversions, thermodynamics,energyconservation,andentropy.Buckle-upinParts4and5inordertotacklethesubjectsofelectricandmagneticforcesandfieldsandridethewavesoflight,sound,andothervibratingdisturbances. Allofthesetopicsparallelnationalscienceteachingstandardsforthephysicalsciencesinmiddleschoolandabove.Thisworktextwillserveasagoodreviewofconceptsforsomestudents,anextraopportunityforotherstoworkwithdifficultconceptsagain,andcanevenserveasateacher’sguideforanexpandedprogramofinstruction. Keytermsappearboldfacedinthetext.Absorbsectionsintroducenewconcepts.Applysectionsallow the reader toexercisehisorherknowledgeof thecontentandconceptsbyansweringquestions,fillingintheblanks,andengaginginshortactivities.Afewexercisesmayrequireadditionalpaper;acalculatormayalsobeuseful.Attheendofeachsection,thereaderisinvitedto“putitalltogether”andtesthisorherunderstandingofthatsection. Workbooks are never a substitute for hands-on opportunities with simple machines,batteries,circuits,prisms,andmagnets.Trytohaveavailableasmanyofthesematerialsastimeandbudgetwillallow.IfyouareamemberoftheNationalScienceTeachersAssociation,there is some quite useful software available at www.scilinks.org for creating and tinkeringwithelectriccircuitsina“virtuallaboratory,”whereyoucanexplodelightbulbsandfrycircuitswithouthavingtoraidtheemergencyequipmentfund. Enjoytheexcitinguniverseofmotion,forces,andenergy!

Introduction/HowtoUseThisBook

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AUniverseofMotion,Forces,andEnergy

A Universe of Motion, Forces, and Energy

Aspaceshuttlecanliftapayloadequalingtheweightof6.6tyrannosaursintoEarth’sorbit,buttodoso,ithastoburn20timesthatweightinfueltocounteracttheforceofEarth’sgravity.Whileyoudon’thavetoexertthatmuch

energytohoistyourselfoutofbed,munchonsomeCheerios™,andcatcharidetoschool,youreverydayactivitiesandthelaunchofarocketallinvolveenergyexpendedtoovercomeorgenerateforcesthatresultinmotion.Physical sciencestudiestherelationshipsbetweenmotion,forces,energy,andtherulesoftheirinteraction.

Todiscovertheserulesofinteraction,scientistsspendalotoftimetakingcarefulmeasurements.Asyoumayalreadyknow,scientistshaveagreedtousemetricunitsofmeasurementssothatscientistsallovertheworldcaneasilymakecomparisons.Those 6.6 tyrannosaurs, by theway,weigh30,000 kilograms(kg),or10,000pounds. Whenwethinkaboutthemorningdrivetoschool,wethinkoftheearthasastationary,ornon-moving,object.Foreverydayactivities, theearthservesasour frame of reference for themotionsandforceswithwhichwedeal.Butwecertainlycould(and sometimes must) consider other frames of reference inphysical science.The earth rotates on its axis at the rate of1,650 kilometers per hour. less energy is required to launchaspaceshuttleinthedirectionofEarth’srotationthanagainstit,soscientistsmustexpandtheirframeofreferencetoincludeamovingEarth.For launchingashuttle intoEarth’sorbit, thesunandotherplanets in thesolarsystemcanbeconsidered

stationary.Ofcourse,weknowthattheplanetsactuallymovearoundthesun,soifweplannedajourneytoMars,forexample,wewouldhavetochangeourframeofreferenceyetagain.Wecouldconsiderthedistantstarsasourstationaryframeofreference. So,fastenyourseatbeltsandpreparetoenjoytherideaswepropelourselvesthroughauniverseofmotion,forces,andenergy.

1. Onatrainridecross-country,thetrees,buildings,andpeopleappeartobespeedingby

thewindow.Thisisbecausethetrainisour .

2. Scientistsusethe systemformakingmeasurements.

3. Physical science studies the relationships between ,

,and .

4. If6.6tyrannosaursweigh30,000kg,thenwhatdoesoneweigh?

Wanttogiveonealift?

5. Formostactivities,the makesahandyframeofreference.



Part 1: Measuring Tools—Meet the Metric System

Our English system of weights and measures has a colorfulhistory, including a length measurement called the foot based ontheshoesizeofakingandan inchdefinedas the lengthof three

barleycornsplacedendtoend.ButEnglishmeasurementscanbeconfusinganddifficulttoconvertintodifferentunits.Scientistsuseametric systemofweightsandmeasurescalledSysteme International d’Unites (SI for short), basedonunitsoften. Thebasicunitoflengthisthemeter,whichisslightlylongerthantheEnglishyard.Prefixesareaddedtoindicatemeasurementsthatincreaseordecreasebyafactoroften.So,adecimeteris0.1m(theprefixdeci meansone-tenth),acentimeteris0.01m(centimeansone-hundredth),andamillimeteris0.001m(millimeansone-thousandth).Toconvertfromonemeasurementtoanother,yousimplymoveadecimalpoint.Ifsomethingmeasures360cm,calculatethenumberofmetersbymovingthedecimalpointtwoplacestotheleft,i.e.,360cm=3.60m. Going in theotherdirection,onedekameter is10m(dekameans ten),ahectometer is100meters(hectomeansonehundred),andakilometer is1,000meters(kilomeansonethousand), i.e.,1km=0.6miles.Thesameprefixesareusedforallmetricunits.Otherprefixesincludemicro(one-millionth)andmega(onemillion).Amicrosecondisone-millionthofasecond,anda megahertzisamillionhertz(seepage35). AsinEnglish,secondsandhoursareusedtomeasuretime.Until1956,thesecondwasdefinedintermsofafractionofthemeansolarday,butthedaylengthisslowlyincreasingastheearth’sspinslows.Thesecondisnowdefinedasthetimeittakesacesium-133atomtomake9,192,631,770vibrations! Thebasicmetricunitofvolumeistheliter,approximatelyaquart.Aliterisalsoequalto100mm3(cubicmillimeters).Areaismeasuredinsquaremeters(m2).1m2isapproximatelythesurfaceareaofacardtable.Massismeasuredingramsandkilograms.1,000kg=1metricton,whichisnearlythesizeofanEnglishton.Forceismeasuredinnewtons,with1newtonbeingaboutone-fifthofapound. Thejouleistheofficialunitofenergy,definedastheamountofworkdonebyaforceofonenewtonactingoveradistanceofonemeter. Temperature is measured in degrees Celsius (°C), instead of degrees

Fahrenheit(°F).Thefreezingpointofwateris0°Cand32°F.°C = °F – 32 x %l;°F =

(°C x(g) + 32. Thetheoretical temperatureatwhichatomscannolongermove(willhavenomorekineticenergy)iscalled0 K(pronouncedzeroKelvin).Thisisalsocalledabsolute zero.Waterboilsat373Kelvin(theword“degrees”isnotused.)

Part1:MeasuringTools—MeettheMetricSystem



Name: Date:

Measuring With Metrics

Somecommonmetricconversionsarelistedbelow:Refertothistableasnecessarywhensolvingproblemsinthisworkbook.

1squaremeter(m2)=10.764squarefeet(ft.2) 1meter(m)=3.28feet(ft.) 1squarefoot(ft .2)=0.093squaremeters(m2) 1millimeter(mm)=0.039inch(in.) 1squarekilometer(km2)=0.386squaremile(mi.2) 1inch(in.)=25.4millimeters(mm) 1cubicfoot(ft.3)=0.028cubicmeter(m3) 1yard(yd.)=0.914meters(m) 1squaremile(mi.2)=2.59squarekilometer(km2) 1mile(mi.)=1.609kilometers(km) 1cubicmeter(cm3)=35.315cubicfeet(ft.3) 1kilometer(km)=0.621miles(mi.) 1cubicinch(in.3)=16,387.064cubicmillimeters(mm3)1hectare(ha)=2.471acres(ac.) 1liter(l)=1.057quarts(qt.)=0.264gallons(gal.) 1acre(ac.)=0.405hectares(ha) 1gram(g)=0.035ounces(oz.)[avoirdupois] 1quart(qt.)=0.946liter(l) 1kilogram(kg)=2.204pounds(lbs.)[avoirdupois] 1ounce(oz.)=28.35grams(g) 1newton(N)=0.2248pounds(lbs.) 1pound(lb.)=0.454kilogram(kg) 1pound(lb.)=4.448newtons(N) Inaddition,1lofwaterweighs1kg;1ml=1,000mm3andweighs1gram.1cubicmeter(m3)ofwaterweighs1metricton.1cubiccentimeterisaboutthesizeofasugarcube.Sometimescubiccentimeters(cm3)arereferredtoas“cc.”1cm3=1cc

Directions: Usethemetricrulerprintedonpage3,theconversiontableabove,andanyotherinformationprovidedonpages3and4tohelpanswerthequestionsbelow.

1. Measurethelengthofyourindex(pointing)fingerfromitstiptoitsknucklejoint.Record

thelength,firstincentimeters,theninmillimeters. cm mm

Now,ifyoueverforgetyourhandyrulerandneedtomeasuresomething,youcanuse

thefingeronyour“handyhand”todosoandfigureouttheactuallengthlater.

2. Howtallisthispageinindexfingerunits?(Youmayhavetoguessafractionofafinger

unittocompletethemeasurement.) fingerunits.Whatisthisincentimeters?

cm

3. Thegraduatedcylindertotherightcontainshowmanymillilitersof

water?(Eachmarkrepresents0.5ml.) ml

4. You’refishingatyourfavoritelakeinJuly.Thethermometersaysthe

temperatureis93°F.What isthetemperatureindegreesCelsius?

(tothenearestdegree) °C

5. Howmanytonsissixmegatons?

6. Convertallofthefollowinglengthstomillimeters. A.12cm= mm B.5inches= mm C.1yard= mm D.1meter= mm E.10feet= mm

MeasuringWithMetrics

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Part 2: The Mechanics of Motion— Measuring Speed and velocity

“Move it!”saysDad,andyouknowyoumustchangeyourposition inatimelymanner—which isprecisely thedefinitionofmotion.Thespeedwithwhichyoumovemost likelydependson the loudnessofDad’sbark.Speed equals the distance traveled(insomemetricmeasureoflength,likemeters)

divided by the time it takes to move that distanceinsecondsorhours:s = d/t.Bymultiplyingbothsidesofthisequationbyt,youwillalsoseethatthedistancetraveled(d)equalsspeed(s)timestime(t).(d = st). If you want to look cool, you might move at aconstant speed—that is, you move the same distanceduringeachintervaloftimemeasured.Ifyougraphdistancemovedagainsttime,yougetastraightlineliketheoneattheright.

Ifyourcoolnesstakestimetogather,youmightmovequicklyatfirst,thenslowdown.Agraphmightlookliketheoneattheleft.

Thespeedatwhichyoumoveatanygivenmomentisyourinstantaneous speed.Youraverage speedequalsthetotaldistancetraveledoverthetimeintervalmeasured.(Averagespeedandinstantaneousspeedarethesamewhenspeedisconstant.) velocity is speed in a particular direction.DoesDadwantyoutocometohimormoveaway?velocitycanberepresentedbyanarrowcalledavectorwhoselengthisdeterminedbythespeedmoved.Thesevectorscanbeaddedorsubtracted.(FirstyoumoveawayfromDad,andthenyouchangeyourmindandmovecloser.)

Part2:TheMechanicsofMotion—MeasuringSpeedandvelocity

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1. Whatisthespeedofacartraveling144kmin90minutesinkilometersperhour?

km/hInmilesperhour? mph

2. IfMarvinrunsataspeedof16km/h,howfarwillhetravelin45minutes? km

3. lookatthegraphbelowthatmeasuresthespeedofarabbitoverthecourseofanhour.

Whatistherabbit’sinstantaneousspeedat30minutes? m/min

Whatisitsaveragespeedfortheentirehour?

m/min

4. Indicate which of the following are speeds

andwhicharevelocities:

A.125cm/sec

B.30km/hnorthwest

C.350m/secnorth

D.520km/h

5. let1cm=200km/h.Inthespacebelow,drawavectorthatrepresentsthenetvelocityof

aplanethattravels300km/hnorth,175km/hsouth,then225km/hnorth.

Part 2: The Mechanics of Motion: Measuring Speed and velocity (cont.)

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Part2:TheMechanicsofMotion:MeasuringSpeedandvelocity

Get Ready, Get Set, Accelerate!

Thestarter’sgunfires.Yourthighstightenasyouboltfromtheblocks.Yougofromastandstill(0velocity)towarp4(orsoitfeels)injustafewseconds.In other words, you have changed velocities, or accelerated. Acceleration (a) equals final velocity (vf) minus original velocity (vo) divided by time

(t) elapsed.a = (vf – vo)/t. Notethatbecauseaccelerationinvolvesvelocity,itisavector.Youdon’tjustspeedup,youspeedupmovingtowardthefinishline.Note,too,thatyourbodyfeelsanychangeindirectionandvelocity,whetheryouareinarace,slammingonthebrakesinacar,orscreamingasyourrollercoastercarinvertsduringthemonsterloop. So,let’ssayyouacceleratefrom0m/secto3m/secin1second.Acceleration=(3m/sec–0m/sec)/1secor3m/sec/sec.Inotherwords,ifyoumaintainthatacceleration,yourvelocitywillincrease3m/secforeverysecondthatpasses.Attwoseconds,velocitywouldbe6m/sec,at3seconds,velocityequals9m/sec,andsoforth.Graphsofaccelerationarealwayscurvedlines. Ichabodwasfasteroutof theblocks,butnowhisacceleration is decreasing. Negative acceleration iscommonlycalleddeceleration.YouleaveIchabodinthedust.Thefinishlinebeckons.Butthenyoufeelaswooshofairandsmellahintofperfume.Beatricepassesyou.Wheretheheckdidshecomefrom? Yourmomisrotatingherarminacircle,urgingyouon.Herarmisaccelerating,too.Although the speed of her circles remain the same, the direction of motion of her arm is constantly changing,meaning thevelocityofherarm ischangingeverymoment—theverydefinitionofacceleration. Can’tdisappointMom.YoubeatBeatricebyanose.

1. Usingtheabovegraph,howfarhasthesprinterrunafter5seconds? After8

seconds? .Whatishervelocityat5seconds? At8seconds?

Whatisheraccelerationbetween5and8secondsintotherace?

(Makesureyougiveallanswersintheproperunits.)

2. Acarisstoppedatastoplight,butfoursecondslateristraveling35km/h.Whatisthecar’s

acceleration?

3. Youaresittingonthecouchwatchingcartoons.Relativetotheearth,areyouaccelerating?

Relative to the sun, are you accelerating? Explain your answer.

4. Arunnerwhopullsahamstringandhastoslowdownis:

A.Negativelyaccelerating.B.Accelerating.C.Decelerating.D.BothAandC.

GetReady,GetSet,Accelerate!

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Name: Date:

Conserving Mother Mo(mentum)

136-kg lineman Duane Dunsmore picks up a fumbleand heads toward the goal line. He knocks 91-kg RockNewtononhiskeisterandscoresatouchdown.Dunsmore’s

team,still behind,begins toplayharder.Theother teambegins tomakemoremistakes.Asportscastersays“MotherMohasshifted,”meaningthatthegame’smomentumhasshifted. Physicalscientistsdefinemomentuminaspecificway:Momentum equals mass (m) times velocity (v). Momentum = mv. So, if mass ismeasuredinkilogramsandvelocityinmeterspersecond,momentumhastheunitskg-m/sec. IfDunsmorewasmoving3meters/secwhenhehitNewton,whatwasDunsmore’smomentum?136kgx3m/sec=408kg-m/sec.IfNewtonwasrunningthesamespeed,whatwashismomentum?ButwhatifNewtonwasrunningfaster?IfNewtonhadbeenrunning5m/sec,hismomentumwouldhavebeen455kg-m/sec,andhecouldhavestoppedDunsmore,eventhoughhewas lighter.Bulletshavesmallmasses,buttheycancreategreatdamagebecausetheirvelocityissohigh.Glaciersmaycreepalongatcentimetersperyear,buttheirmassesaresohuge,theycaneasilyplowdownentireforests. Foragivensetofobjects,the total momentum stays the same unless some outside force acts on those objects.Momentum is conserved(staysthesame)forthatsetofobjects.WhenDunsmoredeckedNewton,themomentumDunsmorelostwastransferredtoNewton.

1. Whatisthemomentumofa0.35-kgblackbirdflyingat20m/sec? (Alwaysgivetheunitsinyouranswer.)

2. Whichobjecthasmoremomentum:ataxitraveling11km/horabaseballpitchedat150km/h?Explainyouranswer.

3. WhatspeedwouldRockNewtonhavehadtobemovingjusttocounteractthemomentum

ofDuaneDunsmoremovingat3mpersecond? m/sec4. Momentumistheproductofanobject’s and .5. Katieweighs68kg,andRoxanneweighs45kg.Botharelongjumpersatatrackmeet.What

isRoxannegoingtohavetodotojumpfartherthanKatieatthemeet?

6. Placethefollowingobjectsinthecorrectorderfromhighesttolowestmomentum,assumingthattheyareallmovingattheirtopspeed:fly,spaceshuttle,bullet,volkswagen,freighttrain.

7. Whenabowlingballhitsthepinsattheendofthebowlingalley,whathappenstotheball’s

momentum?

ConservingMotherMo(mentum)



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AFeelingforForces

F1

F2

F4

F3

Net Force = F1 + F2 + F3 + F4

= 4 + 5 + 2 + 3 = 10

Vector 1 :

Vector 2 :

Vector 3 :

Vector 4 :

A Feeling for Forces

Yoursisterfallsdown.Apowerfulmagnetinajunkyardmovesscrapmetal.Theschoolbusstopstopickyouup.Whatisresponsibleforthesemotions?Forces.Scientificallyspeaking,forces are any kind of a push or pull(includingnudges

andsucks).Gravitymayhavecausedyoursistertofallasitpulledonherunbalancedmass—oryoumayhavepushedher.Magneticforcespulledonthemetalbodyofanoldcar.Thefrictionalforcesofbrakepadstouchingwheelsstoppedthemotionoftheschoolbusinfrontofyourhouse. A force gives energy to an object, either causing it to move, stop, or change direction. Intherealworld,manyforcesmayactonanobjectatthesametime.Gravitytugsatyoursister.Windpushesagainstherbody.Butonlyanunbalanced forcecomingfromaparticular directionwillcausehertofalldown.Becauseforceactsinaparticulardirection,itisavectorlikevelocityandacceleration.Youcanthinkofforcesasarrowswhoselengthindicatesmagnitudeoramountandwhosearrowheadpointsinthedirectioninwhichtheforceisacting.Forcescanbeaddedtogethertogetalargerforceorsubtractedfromeachothertomakeasmallerforce.

Nomotionresultsfromtheactionofbalanced forces.Ifyouandyourbrotherpushequallyhardonyoursisterfromoppositedirections,shewon’tmove(althoughshewillcomplain). Weoften take frictional forces forgrantedbecause theyaresocommon.Frictionalforcesareforcesthatactinadirectionoppositetomotion.Theyarecausedbytinyirregularitiesinsolidsurfacesthatslidepastoneanotherasinthecaseofslidingorrolling friction(asinbrakesandrollerskates)andthe impactof themoleculesofa liquid in thecaseoffluid friction.Fluidfrictionisusuallyasmallerforcethanslidingorrollingfriction,whichiswhythemovingpartsofenginesaregreased.

1. Forcesareanykindofa or .2. TorF?Forcesalwaysresultinmotion.3. lookat thefollowingforcevectors.Measuretheir length incentimeters,andnotetheir

directions.Onyourownpaper,drawonevectorthatrepresentsalloftheseforceswhentheyareaddedtogether.

4. Indicatethekindoffriction(sliding,rolling,orfluid)representedinthefollowingexamples:A.Arunnerslidingintosecondbase:

B. Agirlgoingdownawater-filledslideatanamusementpark: C. Pedalingabicycle:



Name: Date:

Newton’s Big 3

“Newton who? Big 3 what?” you might ask. Sir Isaac Newton (1642–1727)isconsideredbysometobethesmartestpersonwhoeverlived—supernerd#1.Althoughthatopinioncanbedebated,Newtondiddiscoverandinvent

manythingsduringhislifetime,includingthree lawsthatsummarizetherelationshipofforcesandthemotionofobjectsforallthingsintheuniverse(withafewminormodificationsunderexceptionalconditionsdiscoveredbyAlbertEinsteinsometimelater.)

Newton’s First Law:Anobjectatrestwillstayatrest.Anobjectthatismovingwillkeepmovingataconstantvelocityunlessanunbalancedforceactsonit. Pushyouremptydesk.Itmoves,thenstops.Why?Frictionalforcesactinthedirectionoppositetoyourpush.Ifyouputwheelsunderyourdesklegs,itmovesfartherwiththesamepush—lessfriction.Iftherewerenofrictionorotherforces(likeawallattheothersideof theroom)actingagainstyourpushforce, thedesk

wouldmoveforever.Thistendencytokeepmovingiscalledinertiaanddependsonthemassoftheobject.Achairwillmovefasterwiththesamepushthanthedesk.Thedeskhasmoremass,andthusmoreinertia. NotethattheFirstlawstatesthatanobjectwillmoveataconstant velocityunlessanunbalanced forceactsonit.Whenanunbalancedforceactstochangeanobject’svelocity(directionand/orspeed),thatobjecthasbeenaccelerated (seepage7).ThisleadstoNewton’s Second Law: Theforceneededtomoveanobjectisequaltotheproductofthatobject’smassandacceleration.Writtenasanequation,it isF = ma.Theunitofforce,honoringSirIsaac,iscalledanewton. In themetricsystem,onenewtonof force isneeded toaccelerateonekilogramofmassattherateofonemeterpersecondpersecond(1N=1kg-m/sec/sec).Ifyoukeepaccelerationconstant,youcanseethat it takesmoreforce(andthusmoreenergy)tomovethemassofatruckthanamotorcycle. Newton’s Third Law:Foreveryaction,thereisanequalandoppositereaction.Throwaheavyballawayfromyou,andthislawmaynotbeobvious,becauseyouareusedtodealingwiththeforceoffrictionofyourfeetagainsttheground.Dothesamethingwhilestandingonaskateboard,andyouwillcertainlynoticetheskateboardmovingintheoppositedirectionfromyourthrow.Thesamethingwillhappenifyousteptooquicklyfromanunanchoredboattothedock.Youcouldgetwet,ifyou’renotcareful.

1. Whatistheforceinnewtonsneededtomovea1,500-kgvehicleatanaccelerationof3

m/sec/sec?

2. Whichhasmoreinertia,a150-kgsumowrestlerora100-kgaccountant?

3. HowdoesabirdflyingillustrateNewton’sThirdlaw?

Newton’sBig3

Answer Keys

AnswerKeys

A Universe of Motion, Forces, and Energy (Page 2)1.frameofreference;2.metric;3.motion,forces,energy(anyorder);4.4,545.5kg;5.earth

Part 1: Measuring Tools: Measuring With Metrics (Page 4)1.variableanswers;2.variableanswers;3.51.5;4.34;5.6million;6.A.120;B.127;C.914.4;D.1,000;E.3,048

Part 2: The Mechanics of Motion: Measuring Speed and velocity (Page 6)1.96;59.7;2.12;3.1.67m/min,1.5m/min;4.A.Speed;B.velocity;C.velocity;D.Speed;5.vectorwillbe1.75cmlong(350km),pointingnorth.

Get Ready, Get Set, Accelerate! (Page 7)1.45m,108m,15m/sec,24m/sec,3m/sec/sec;2.8.75km/sec/sec;3.No,Yes.Earthisrotatingandrevolvingaroundthesun.4.D.

Conserving Mother Mo(mentum) (Page 8)1.7kg-m/sec;2.Taxi,becauseitweighssomuchmorethanabaseball.3.4.5m/sec;4.mass,velocity(anyorder);5.Runfaster.6.Spaceshuttle, freight train,volkswagen, bullet, fly; 7. Most of it istransferredtothepins.

A Feeling for Forces (Page 9) 1.pushorpull;2.F;3.vector4centimeterslongpointingright;4.A.Sliding,B.Fluid,C.Rolling

Newton’s Big 3 (Page 10)1.4,500N;2.Thewrestler;3.Theforceofitswingbeatagainstairpropelsthebirdforward.

Free Fa-a-all and Gravity (Page 11) 1. 29.4 m/sec; 2. Itdecreases rapidly because force decreases by the inversesquare of the distance between objects. 3. Weight willdecrease;masswillstaythesame.

Forces in Fluids (Page 12) 1. The ship’s overall density(including the density of the air-filled hull) is less than thedensityofanequalvolumeofwater.2.Airmassesflowfromareasofhighpressure toareasof lowpressure,producingwind.

Work and Power () 1.joules;watts;2.variable;3.Divideworkby10;divideworkby4;4.AandCarework;5.1,000,000watts;6.F

Part 2: The Mechanics of Motion: Putting It All Together (Page 15)CONTENT: 1. distance, time, direction; 2. T; 3. The totalmomentum (mv) of a group of objects remains the same,althoughitmaybetransferredamongobjectsinthegroup;4.vectors;5.F=ma;6.A.7.Bernoulli’s;8.W=Fd,P=W/timeorworkequalsforceusedtomoveanobject;powerequalshowfastworkhappens;9.simplemachinesCONCEPT: 1.Severaldifferentwedges;2.Theforceusedtomovethegroceriesisperpendiculartothegroceries;3.Thetimeittook.

4.Thesecondperson’saveragespeedwasgreaterthanthefirstperson’sconstantspeed;5.It takesawhiletoslowthemomentum of large objects; 6. Gravity, air movements; 7.Answerswillvary.

Part 3: All About Energy: Energy, Let Me Count Its Forms (Page 16) 1.A.Chemicalenergy;B.Nuclearenergy;C. Electromagnetic energy; D. Heat energy; E. Mechanicalenergy;2.sun;3.theabilitytodowork

Kinetic Energy: The Energy of Motion (Page 17) 1.Kineticenergyincreaseswiththesquareofvelocity;2.work;3.22,500J;4.Momentum=mvandhasdirection;K.E.=mv2/2andisnotavector;5.potential,kinetic(anyorder);6.F

Potential Energy: The Energy of Position (Page 18) 1.position;2.F;3.2,058,750J;4.6,669,000J;5.B.;6.heightandweight(anyorder)

Energy Conversions (Page 19) 1. chemical, heat,mechanical;2.energyconversions;3.Mechanicalenergyofwater,mechanicalenergyofmovingturbines,electricenergy,mechanicalenergyofdryerfan,heatenergyofdryercoils.4.Atrelease;whenithitsthegroundandwhenitstopsrolling;justbeforethefirstbounce;5.A.solarcells;B.burningfossilfuel,amatch,etc.;C.friction

Moving Heat Around: Thermodynamics (Page 20) 1.Noconvectionorconductionofheatthroughthevacuum;noheatlossbyradiationthroughtheshinyliner.2.Thereissomelossbyconductionthroughthestopperandlid.

Conserve Energy—That’s the Law! (Page 21) 1.F;2.Fossilfuels;heat,mechanical,electromagnetic;3.Underveryhightemperatures and pressures, mass can be converted toenergy;4.heat

The Laws of Thermodynamics (Page 22) 1.600J;2.Firstlaw;3.Therearealwayssomeheatlossesinanymachine.

Entropy: A Measure of Disorder (Page 23) 1.heat;2. Somewhat disordered and chaotic; 3. Eventually, theuniversewillallbeat thesame temperature,and therewillbe no energy to do work. 4.When there is a concentratedsourceofenergy,likethesun.5.lightandotheremradiation,electricity,fossilfuels;6.C.

Part 3: All About Energy: Putting It All Together (Page 24)CONTENT:1. joules;2.C.;3.kinetic;4.weight;5.heatandlight; 6. conduction, convection, radiation (any order); 7.Energy can neither be created nor destroyed by ordinarymeans.8.theFirstlawofThermodynamics;9.FCONCEPT:1.Heatfromradioactiveelementsincreaseswithdepth;2.Potentialenergy;3.SirSeymour;hiscannonballswill



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