Y6/AS Physics final exam 11_12 Unit 1_answers

8/2/2019 Y6/AS Physics final exam 11_12 Unit 1_answers

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~,',kMERICAN ACADEM,LARNACA, ' , " " , " " , "" ' "~ , '. - . '. 'FINAL EXAMINATIONS:2011 _12cPHYSICSYear 6 [Advanced Subsidiary]Unit 1: Ph sics on the GoFriday 27 April 2012 - 7.30 a.m. Paper ReferenceTime:Ihour 30minutes PHOI/OlTeachers A. G. Chimonides / P. Bur essNo. of students 10Write your name hereI Surname I Other names

ScientificcalculatorRuler

Instructions Use black ink or ball-point pen (black/blue). Fill in the boxes at the top of this page with your names. Answer all questions (there are 20 questions). Answer the questions in the spaces provided - there may bemore space than you need.Information The total mark for this paper is 80. The marks for each question are shown in brackets - use this as a guide as to how much timeto spend on each question. Questions labelled with an asterisk (*) are ones where the quality of your writtencommunication will be assessed - you should take particular care with your spelling,punctuation and grammar, as well as the clarity of expression, on these questions.

The list of data, formulae and relationships is printed at the end of this booklet. Candidates may use a scientific calculator.Advice Read each question carefully before you start to answer it. Keep an eye on the time. Try to answer every question. Check your answers if you have time at the end.

Turn over


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-~-Answer ALL the questions.

For questions 1-4, select one answer from A to D and put a cross in the box (~). If youchange your mind, put a line through the box (S) and then mark your new answer

with a cross (~).1. Which of the' following quantities is a vector?

D A densityD B massD C strain,~ D weight (Total 1 mark)

2. Two wires made of the same material but of different lengths and diameters are joined endto end and used to support a vertical load. If the weight of each wire is neglected, eachwire must have the sameD A extensionD B strain~ C tensile force (D D tensile stress (Total 1 mark)

3. Newton's third law tells us thatD A actions usually have a reactionD B weight and normal contact force are always equal and oppositeD C moving with constant velocity is the same as being at restj 2 g D forces always arise in pairs (Total 1 mark)

4. A n athlete throws ajavelin. Just as it hits the ground the javelin has c l horizontal velocitycomponent of 20 m S-l and a vertical velocity component of 10m s'. The magnitude ofthe javelin's velocity as it hits the ground is I{) .).-' U-r z 7 - ~ - 'S 'AD BIX CD D 30ms-1 (Total 1 mark)

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-3-In questions 5_,-~which of the following graphs best represents the quantities describedwhen they are plotted on the y- and x-axes. Each graph may be used once, more thanonce or not at all.y y

xA BVariable on y-axis

!; The kinetic energy of a car accelerating.uniformly from rest

B o

The acceleration of a feather falling near tothe Moon's surface

- :1 A 0 B

y y

x

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x xc DVariable on x-axis

Displacement from starting position

c o D o(Total 1 mark)

Height above the Moon's surface

c o D . o(Total 1 mark)

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1 . A ball bearing is dropped through a liquid and its terminal velocity measured.The experiment is repeated at a different temperature.Which row could correctly describe this second experiment?

I Temperature ViscosityTerminal velocity

IA ! lower I fasterI greater !i1 - -- I~ B I lower greater - , slowerI ;ijID c I higher greater slowerI- - - - rD D ! higher smaller slowerI

(Total for Question + = 1 mark)~.Velocity can be found from the

D A area under a displacement-time graphD B area under a force-time graph~ C gradient of a displacement-time graphD D gradient of an acceleration-time graph

(Total for Question 8= 1 mark)J A freely falling object on Earth has a speed of 5.0 m s:'.

After falling a further 20 m its speed is '" '" - = " " - " " ~D A 15 ill S-1 ::L ){ B 20 m S-ID C 25 m S-ID D 45 m S-I

(Total for Question 9 = 1 mark)

./S


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-5-

10..The acceleration of free fall on a particular planet is 8.0 m S-2. An object is droppedfrom a height and hits the ground after 1.5 s. From what height was it dropped?

1' i0 A 6.0m s -:"'-.\~ l. ~~tz ,~ B 9.0m ~)


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-b-

Comment on his statement.

SECTIONBAnswer ALL questions in the spaces provided.

*11 (a) Explain the difference between scalar and vector quantities.(1)

~~~~h..~d...\.rt~~ .5 "

(b) When asked to run one complete lap around a track, a student says, "However fast Irun, my average velocity for the lap will be zero".

(3)

\r.:~'~;;~::'f.\..~~~- -~~

~~\~


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- "f-/ J . . , There has been a proposal to build a train tunnel underneath the Atlantic Ocean from

England to America. The suggestion is that in the future the trip of 5000 km could take'as little as one hour.Assume that half the time is spent accelerating uniformly and the other half is spentdecelerating uniformly with the same magnitude as the acceleration.(a) Show that the acceleration would be about 2 m S-2.

(2)'~::1:~}r.,~~)("v.

\f"".... ......~ .A -""

\5--, -

. ..T .,\ ...~~::: ..~ ..~ ... ,;.~~~~

\~'> -(b) Calculate the maximum speed.

(2)

.. ..Speed = 6.YQ:t>~s. .-Cc)Calculate the resultant force required to decelerate the train.

mass of train = 4.5 x 105 kg(2)

......( ~ ~." :: 1.?~..g~. > < " ,:S~s.~~ , , , ,.

(Total for Question I~ = 6 marks)

.. -/8. ' .


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13 ,.(a ) What is meant by Newton's first law of motion?(2)

...........................................r. ~~ k ~.f. ..::O .(b) Newton's third law identifies pairs of forces.

(i) State two ways in which the forces in a pair are identical.(2)

. .. .. . ... ... .. .. . .. .. .. .. .. .. . .. . . .. . . . .. .S \.1 > .(. \.~ .~ ~ q~'r.i..~ (. ~v.-".~ .

(ii) State two ways in which the forces in a pair differ. _

I (2)1 < l,rt,< .I,,~r~""""'\.. .~"'< ..k~--!I .

(iii) One of the forces acting on a car can be described as follows:'The Earth exerts a downward gravitational force of 12 000 N on the car'.Describe its Newton's third law pair force.

(2)I ~ ~\\ ~ ~~~b~\h..~~~ .....I '

............. : ~?"..9.VV.N . ~ ~ ~h .(Total for Question 13 = 8 marks)


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-f-

1 ' - 1 . Archer fish spit water droplets at insects from the surface of the water.(a) The Archer fish spits a droplet of water with a velocity of 3.5 m S-1 at an angle of

70 to the horizontal, aiming for an insect on a branch above the surface of the water.The horizontal distance to the insect is 0.4 m.

(i) Show that the initial horizontal component of velocity for the droplet is about1 -1ms. 1..s~'i.'\ (2)

.........f~. ~,:~~\ .(ii) Calculate the vert~cal distance, y, to the insect if the droplet hits the insect.

( S). : : 1

" "'.......S=\f.::-:-.~ .

1-l}~~>~\~?\~~.,).:;: .---2 . . , . . . c . . . .' ) 'f .< {\ ~ ')-~

-:..

Distance =().S..?~.............. ..-(b) Sketch the path of the water droplet on the diagram above.(1)

(Total for Question (Lf,= 8 marks)

... 10

I


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-10-

Figure 1

Lift

Not to scale

Drag

WeightTension

Figure 2Figure 2 shows a free-body force diagram for the kite.(a) Sketch a labelled vector diagram to show that the four forces are in equilibrium.

(1)

' " '1 1


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-11-(b) The lift is 4.3 N, the drag is 6.0 N and the weight is 0.44 N.

>i Calculate the tension in the string. State its magnitude and direction from thehorizontal.

-r - 1 - - 'v .. . (Jl.-\\"\.......... '\ ." " T ~ 1 < " 6 ' Co}J............ ":\ .

u 1"u -:: u ib .~Q ~u1 .:J :~c...~uQ ~~~'?.~~

s-o

(4)

-= f:JA J .

(2)

(2)

(Total for Question 1 5 = 9 marks)

E , U J->...---..--- ......."'-r .

.._ .._ -. _ ..~~:}P.J. .

Magnitude of tension =Direction of tension from the horizontal = .. '3 30

(c) (i) The wind speed decreases so the girl flying this kite walks into the wind at aconstant speed of 2.0 m S-I to maintain the forces shown. Calculate the workdone by the girl as she walks 25 m.

Work done = ..lS0:>.(ii) Calculate the rate at which work is done by the girl.

- = . . .. l' f l..~

Rate at which work is done =\2~

" '1 2 .

I

I1I


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-/~~* J 6 In a demonstration of energy transfer, a large pendulum is made by suspending a 7.0 kg

bowling ball on a long piece of wire."A student is invited to pull the ball back until it just touches her nose and then torelease it and stand perfectly still while waiting for the ball to return.

The following instructions are given:

Do not push the ball - just release it:Do not move your face before the ball returns.

(a) Explain this demonstration and the need for these instructions.(6)

.~*.~ ..,=\\5~~~~~~~:=>'~~~'7l:>,,~? ~..~~\,S~~>~~\o~~ ~ . .

.~ ~"VJlA,.V'~.!K.. ~b~ ~ ~.~~~n~Y.-. . ~.i.)C 1 > ~ ~ '1~.t~~ rtl.~ ~.~~;...~~h~'\.~

.)\;U~)~ ,,'(W)~.~~k.~v.Jt. ~\..~ ~k ~ ~.\\ ~~ v-.~L.~k.i\~~t

......k..~~.~ .

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(b) The bowling ball is raised through a vertical distance of 1.5 m.". (i) Calculate the gravitational potential energy gained by the ball.

. .......>.~ ' "..:; ~b l>\ .(2)

Gravitational potential energy =lcruS(ii) Calculate the speed of the ball at the bottom of its swing.

(Total for Question/6: = 10 marks)

(2)

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The health hazard of volcanic ash can be assessed by determining the number of particlesof less than diameter 4 urn in a sample. This is known as grain-size distribution analysis."A cheap technique used to determine grain-size distribution is sedimentation. This isbased on the application of Stokes's law. The particles are allowed to fall through a liquidof known density and viscosity. The terminal velocities of the particles are measured.

(i) Add labelled arrows to the diagram to show the three forces acting on a particleas it falls through the fluid. .

(ii) State the relationship between these forces when the particle is falling at terminalvelocity.

\u = - \ ) ~ U........ 7.~ ..................................... (1)(iii) Write down an expression for the weight of the particle in terms of its radius r

and density Pash ..... ..N ? ~.O. ~~.~ o . : J . : . ; ' " . ~ . ~ .

(iv) Hence show that r is given by

where 1 ] is the viscosity of the liquid, v is the terminal velocity of the particle andPr is the density of the fluid.

~ ~........:tl.(~~=~:: r.:\'.\.q(..~ :x 1:Rv:~(~~ .. . . . . . . . 2 - . ' r . . : : - : . ~ c . . : k . .? 1 , . :~T.. ;z.:(:f~~... . . ........(.~.tb~.~~ ..:-:~.~~.;> .) :: 1..~.~ ."'- i. . . . . . . . I r . ' '? : 1 .1 c \.~ : : : : - ? : < : . . ~ ~ . '1'~"""""""'"--\ - - -. . . . . 1 . . ! > ( \ - . : : " ~. . : L o ! > . . l ~ " " , ' "~t\.

(2)

(2)

( 3 )... /1:

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(v) Explain how the terminal velocity would differ for a larger particle..................... " ...

't.-...~ ~ ,,:r"\. . If A' -:1(' - - \ ..\... -

(vi) State why it is important to keep the temperature constant when taking thesemeasurements ...: ,, : ~ ~ Q .

(Total I[ marks)

(2)

(1)

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-/6-Leaveblank* '1 . 8 A sign at a railway station advises passengers to keep back from the platform edge. This

is because passing trains may cause turbulence.

~ Keep back from ~.~ the platform edge i~ Passing trains cause air turbulence { i.-~ .~. . _ 1 11~;;;'.~1I' l'/- - ,> . .~J


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-If-

1 '9 The photograph shows the top of an inspection cover for a drain.

(a) The cover is marked 'ductile'. It is made from ductile iron, which was invented in1943. It replaced the previous form of cast iron, which was more brittle.Explain the meaning of the following terms:

(2)\ - '

...~~.\~~ .(b) The cover is also marked '35 kN'. This refers to the load it must be able to support.

Calculate the mass that would produce this load.(2)

..Q'trt:>.".)..................... .Mass = ...} ..~~3 .. .-'(Total for Question /9= 4 marks)

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2 . . 0 A sample of wood is tested using the following arrangement.I Beam andf---- clampl JWood 11----11 Xsample ( I~J--Clamp

~ LightI /1 1 Ill/Platform

The wood sample is clamped securely to a supporting beam. A light platform issuspended from the wood sample using another clamp.The dimensions of the wood sample at X are known. Masses of 2 kg are added to theplatform during the testing process.(a) The wood sample breaks at X when the total suspended mass is 84 kg. The

cross-sectional area at X is 1.3 x 10-5 rrr'.Show that the ultimate tensile strength is about 6 x 107 Pa.

(3)

..(L:::S - z : . . ...


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-/1-(b) Explain why this method of testing may produce a larger value than the true ultimate

tensile strength.(2)

.................~, ~~ ~~.~~~v.k o.,..t\~~n.\:;.:J.~~h,;.~ ~ ~ ........~ ...I

(c) Explain why the wood sample used for this test has the shape shown.(2)

(d) Samples of wood of the same type are not entirely uniform. What should be done toensure reliable results are obtained when carrying out this test?

(1)~......~ .

1 ~ ( T _ o _ t a _ I _ ~ ~ o _ r ~ Q ~ u _ e _ s t _ i o ~ n _ ~ ~ _ = _ 8 _ m_ a _ r k s ~ ) _I." m ; *1

TOTAL FOR SECTION B = 70 MARKSTOTAL FOR PAPER = 80 MARKS

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List of data, formulae and relationships

(close to Earth's surface)cceleration of free fallElectron chargeElectron mass

g = 9.81 m S-2e = -1.60 x 1O-19C

m e =9.11 x 1O-31kg1 eV = 1.60 x 10-19 Jg=9.81Nkg'h =6.63 X 10-34 J s

(close to Earth's surface)ElectronvoltGravitational field strengthPlanck constantSpeed of light in-a vacuumUnit 1

c = 3.00 x 108m s'

MechanicsKinematic equations of motion v = u + ats = ut + YzaP

v2 = u2 + 2asForces r . F = m ag=Flm

W=mgflW = FosE = Yzm v 2k!lE = mgtshgray

Work and energy

MaterialsStokes' lawHooke's lawDensityPressure

F = GnnrvF=kfup =mlVp =FIA

Young's modulus E = (J IE: whereStress (J =F/AStrain E : = Sx/x

Elastic strain energy

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Y6/AS Physics final exam 11_12 Unit 1_answers