Level 1 Physics, 201090183 Demonstrate understanding of mechanics

in one dimension

Credits: Five2.00 pm Thursday 25 November 2010

Check that the National Student Number (NSN) on your admission slip is the same as the number at the top of this page.

You should answer ALL the questions in this booklet.

For all numerical answers, full working must be shown. The answer should be given with an SI unit.

For all ‘describe’ or ‘explain’ questions, the answer should be in complete sentences.

Formulae you may find useful are provided in the Resource Sheet L1-PHYSR.

If you need more space for any answer, use the page(s) provided at the back of this booklet and clearly number the question.

Check that this booklet has pages 2–10 in the correct order and that none of these pages is blank.

YOU MUST HAND THIS BOOKLET TO THE SUPERVISOR AT THE END OF THE EXAMINATION.

For Assessor’s use only Achievement Criteria

Achievement Achievement with Merit

Achievement with Excellence

Identify or describe aspects of phenomena, concepts or principles.

Give descriptions or explanations in terms of phenomena, concepts, principles and / or relationships.

Give explanations that show clear understanding in terms of phenomena, concepts, principles and / or relationships.

Solve straightforward problems. Solve problems. Solve complex problems.

Overall Level of Performance (all criteria within a column are met)

901830

9 0 1 8 31

For Supervisor’s use only

© New Zealand Qualifications Authority, 2010All rights reserved. No part of this publication may be reproduced by any means without the prior permission of the New Zealand Qualifications Authority.

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This page has been deliberately left blank.

You are advised to spend 50 minutes answering the questions in this booklet.

All formulae are provided on the separate Resource Sheet L1-PHYSR.

QUESTION ONE: SPRINT RACE

(a) Terrycompletesa100mracein11.5s.

Calculatehisaveragespeed.

averagespeed=

(b) Thedistance-timegraphforTerry’sraceisgivenbelow.

0

0

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Dis

tanc

e (m

)

Time (s)

Terrystartsracingassoonashehearsthestartinggun.

Onthegraphabove,completeapossiblelineforthefirst10moftherace.

Giveareasonfortheshapeofthelineyouhavedrawn.

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LiamandJonathanalsocompetedinthesame100mrace.Thevelocity-timegraphsfortheirracearegivenbelow.

0

0

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Velocity (m s–1)

Time (s)KeyLiam

Jonathan

(c) UsetheinformationgiveninthegraphtocalculatethedistancecoveredbyLiambetween4and10seconds.

distance=

(d) Liamhasamassof72kg.

UsetheinformationgiveninthegraphtocalculateLiam’smaximumkineticenergyduringtherace.

maximumkineticenergy=

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(e) Jonathanreacheshismaximumaccelerationbetween0.25and1.00s.Duringthisperiodhecoversadistanceof1.5m.Hismassis78kg.

Usetheinformationgiveninthegraphtocalculatethepowerrequiredtoproducethismaximumacceleration.

power=

(f) UsethegraphstocompareandcontrasttheperformanceofLiamandJonathan,intermsoftheirspeedandacceleration.

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QUESTION TWO: BUNGEE JUMPING

www.theafricatravelblog.com/wp-content/gallery/bungee-jumping-in-south-africa/img_0085.jpg

(a) ThephotographaboveshowsLafiacceleratingdownwardsduringabungeejump.

Onthephotographabove,labeltheforcesactingonLafi.

(b) Attheinstantshowninthepicture,Lafihasanaccelerationof7.2ms–2.Shehasamassof65kg.

Calculatethesizeoftheupwardforceactingonherbody.

upwardforce=

(c) Lafihasamassof65kgandshefallsfor50mbeforethebungeecordbeginstostretch. Calculatethegravitationalpotentialenergylostduringthe50mfall.

energy=

For copyright reasons, this resource cannot be

reproduced here.

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(d) Lafistartstodecelerateafterthebungeecordbeginstostretch.Whenthebungeecordhasstretched8.0m,shecomestoacompletestopandthebungeecordhasgained37700Jofenergy.

CalculatetheaverageforceappliedbythebungeecordonLafitobringhertoastop,andstatethedirectionofthisforce.

averageforce= direction=

(e) Thebungeeoperatordoesnot wrapthecorddirectlyaroundherankles.Instead,awidepaddingiswrappedaroundheranklesandthenthebungeecordisattachedtoit,asshowninthediagram.

Usingaphysicsidea,explainwhyitisbettertoattachthebungeecordtoawidepaddingthantowrapitdirectlyroundherankles.

For copyright reasons, this resource cannot be

reproduced here.

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QUESTION THREE: RESCUE BOATS

www.lrmfa.org/equip/equip07.asp

(a) Thecombinedmassofarescueboatanditscrewis420kg.Theboatexertsapressureof323Paonthewater.

Calculatetheareaoftheboatthatisincontactwiththewater.

area=

Theboathasavelocityof6.0ms–1totheright,relativetowater.Thevelocityofthecurrentis2.0ms–1totheright.Apersononthebeachisjoggingatavelocityof1.0ms–1totheleft.

(b) Inthespacegivenbelowdrawlabelledvectorstorepresentthethreevelocityvectors.

(c) Useyourvectordiagramtocalculatethevelocityoftheboatrelativetotheperson.

relativevelocity=

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reproduced here.

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Duringanemergency,theboatislaunchedusingaramp.Theboatisplacedonatrolleyandthenitislowereddownorpulleduptherampusingacableandanelectricmotor.

Ononeoccasion,theboatandthetrolleyarehauleduptherampataconstantspeed.Thetensioninthecableis1800Nandthelengthoftherampis6.0m.Theverticalheightoftherampis3.2m.

3.2 m

trolley

6.0 m

(d) Calculatethecombinedmassoftheboatandthetrolley.

mass=

(e) Intermsoftheconceptsofforceandenergy,explainwhyitiseasier:

(i) tohaultheboatupusingaramp,ratherthanliftingitverticallyup

(ii) touseatrolleytohaultheboatuptheramp,asshowninthediagramabove.

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Question number

Extra paper for continuation of answers if required.Clearly number the question.

90

18

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