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1993 AP PhysicsB Examination with Key

Copyright O 1993 by College Entrance ExaminationsBoard and Educational Testing Service All rights reserved

^X ,^F Q,u l)r,u _, 61. -bV (,vt v:t-oF

l. In which of the followingsituationswould an object

be accelerated? I. It moverin a straightline at constantspeed. I[. [t moveswith uniform circularmotion. III. It travelsas a projectilein a gravitationalfield with negligibleair resistance.

(A) I only (B) III only

3 . An ideal springobeysHooke'slaw, F : - kx. A massof 0.50kilogramhung verticallyfrom this springstretchesthe spring0.075meter.The valueof the force constantfor the spring is most nearly (A) 0.33N/m (B) 0.66N/m (c) 6.6 N/m (D) 33 N/m 66 N/m

I

H

I and II only II and III only I. II. and III

A ball falls straightdown throughthe air underthe influenceof gravity.Thereis a retardingforce .F on theballwithmagnitudegivenbyF = bu, where u is the speedofthe ball and 6 is a positiveconstant. The magnitudeof the accelerationa of the ball at any time is equalto whichof the following? (A)g-,

4 fru;

6

@\'-H

il.*o

(c') c + b;

(D)f

t

-/\n ' 0c - bl. ilAq,-

@) * .l

A1-'vr

trllk-bV

Y^

The figure aboveshows4r@serr,ucircuter tract whoseendsareat a verticalheight lr. A block placedat point P at one end of the track is released from restand slidespastthe bottom ofthe track. Which of the following is true of the height to which the block riseson the other sideof the track? (A) It is equalto hl2n. (B) It is equalto hl4. (C) Itisequal to hl2. (D) It is equalto &. f,E) It is betweenzeroand h; theexactheight dependson how muchenergyis lost to friction.

V tv ll-a -a l"-;)i, Afuo,r&

I

.l

5. An objectis releasedfrom reston a planetthat has no atmosphere.The objectfalls freelyfor 3.0meters in the first second.What is the magnitudeof the accelerationdue to gravity on the planet?

(A) (B) @ (D) (E)

1.5mis2 3.0m/s' 6.0 m/s' 10.0m/s2 12.0m/sz

6. lf SpacecraftX hastwicethe massof Spacecraft I, then true statementsabout X and I include which of the fiollowing? I. On Earth, X experienoestwice the gravitational force that Y experiences. II. On the Moon, X has twicethe weightof I/. III. Whenboth arein thesamecircularorbit. X has twicethe centripetalaccelerationof Y. (A) (B) $ (D) (E)

I only III only f and II only II and III only I, II, and III

4?='{woo .

w,-f"o

7. Two pucksare attachedby a stretchedspring and are initially held at reston a frictionlesssurface,as shownabove.The pucksare then releasedsimultaneously.If puck I hasthreetimesthe massof puck II, which of the following quantitiesis the samefor both pucksasthe springpulls the two puckstoward eachother? (A) Speed (B) Velocity (C) Acceleration (D) Kineticenersv @ MagnitudeoTmomentum Gr*eqrvahA, ^

ok ilAn^\eqA/''4,-

8. The two spherespictured abovehaveequal densities and are subjectonly to their mutual gravitational attraction.Which of the following quantitiesmust have the saqe magnitudefor both spheres? (A) Acceleration (B) Velocity (C) Kinetic energy (D) Displacementfrom the oenterof mass i€j c"iuitational force c,6rra.[i. opg":,i< 9. When an objectoscillatingin simpleharmonic motion is at its maximumdisplacementfrom the equilibriumposition,which of the following is true of the valuesof its speedand the magnitudeof the restoringforce? Speed

RestoringForce

@tZero

Maximum

(B) Tnro

7*ro

(c) 2I maxJmum

I tmarumum

(D) Maximum

I tmilomum

(E) Maximum

Zmo

ltl'tf* ?{'

t0. Which of the following is true when an object of mass ,?r moving on a horizontal frictionless surface hits and sticks to an object of mass M > m, which is initially at rest on the surface? (A) The collision is elastic. (B) All of the initial kinetic energy of the lessmassiveobject is lost. (C) The momentum of the objects that are stuck together has a smaller magnitude than the initial momentum of the less-massiveobject. ". Th" speedofthe objects that are stuck together (E will be less than the initial speedof the lessmassiveobject. (E) The direction of motion of the objects that are stuck together depends on whether the hit is a head-on collision. l l. Two objects having the same mass travel toward each other on a flat surface, each with a speedof 1.0 meter per second relative to the surface. The objects collide head-on and are repor"tedto rebound after the collision, each with a speedof 2.0 meters per second relative to the surface. Which of the following assessmentsof this report is most accurate? (A) Momentum was not conserved,therefore the report is false. (D) If potential energy was releasedto the objects during the collision, the report could be true. (C) If the objects had different masses,the report could be true. (D) If the surface was inclined, the report could be true. (E) If there was no friction between the objects and the surface, the report could be true.

12.An automobilemovesat constantspeeddown one hill and up anotherhill alongthe smoothlycurved surfaceshownabove.Which of the following diagramsbestrepresents the directionsof the velocityand the accelerationof the automobileat the instantthat it is at the lowestposition,as shown? (A) -+o I

la i

@

_+D tI

lo (c)

---!+ +A

(D) +o #a

(E) 4"

r3. Which of the following will causethe eloctricalresis-

Questionsl5-16 rcfer to the circuit shownbelow.

tanceof certainmaterialsknown as superconductors to suddenlydecreaseto essentiallyzero? (A) Increasingthe voltageappliedto the material beyond a certain threshold voltage (B) Increasingthe pressureapplied to the material beyonda certainthresholdpressure ($ Cootltrg the material below a certain threshold v temperature (D) Stretching the material to a wire of sufficiently small diameter (E) Placing the material in a sufliciently large magneticfield

t 4 . Kirchhoffs loop rule for circuit analysisis an expressionof which of the following? (A) Conservationof charge Conservationof energy Ampdre'slaw (D) Faraday'slaw (E) Ohm's law

I

3pF 15.The equivalentcapacitancefor this network is most neady

(A) l0/7pF (B) 3l2trF 713trF 7 trF 14pF

ffi

16. The chargestored in the S-microfaradcapacitor is most neady (A) 360pC 500pC 710pC (D) 1,100pC (E) 1,800pC

Qzorl- s,'0[-)

I

= 9upL

re, L-l

ffi u ;)

fr1,v

lonT'eL

%*'

-\e ,

*

,i' - - -,-{u r

& - - - -,-- - - #-

---€

-fT-i--t17. Twolargeparallelcondrctingplates p and p are connectedto a batteryofemf g, as shownaFove, A test_charge is placedsucccssivelyat points I, II, ald III. If edgeeffectsare negligible,the force on the chargewhenit is at poiniili is ' (A) of equalmagnitudeand in the samedirection as force on.thechargewhenit is at point I /R ^the (yl oI equalmagnitudeand in the samedirectionas the torce on the chargewhenit is at point II (C) equalin magnitudeto t-heforceon tt" ftrarge whenit is at point I, but in the opposite dirotion (D) much greaterin magnitude than the fiorce on the chargewhenit is at point II, but in the samedirection (E) much lessin magnitudethan the force on the 9!arg" when it is at point II, but in the same direction

n.M

f

a

I 18. The direction of the magnetic field at point .R caused by the currcnt .{ in the wire shbwn above is (A) (B) (C) (D)

@

to the left to the right toward the wire into the page

outofthlfage

19. T\vo long parallelr+,ires.are sgparatedby a distane d, as shown above.One wire ca*es a sLaiy current f into the plane of thc pagewhile thi other'wire carries 3 sleadycurrent I out of te page.At what points t!.e ntangof the p-ageaoa oirtslOettr'ru1.res, in Dcsrdes potntsat infinity, is the magneticfielddue to the currentszero? (A) Only atryint p (B) At all points on the line ,S,S' (C) At a-llpoints on the line connecting the two wircs (D) At all points on a circle of radius 2d centered on Point P @ nt nopoints

Questions2G22 relateto the following circuit diagram, which showsa battery with an intcrnal resistanceof 4.0 ohms connectedto a l6ohm and a 2Gohm rcsistor in scries.The current in the 20-ohm rcsistor is 0.3 amperes.

16(}

23. If thc gasin a containcr apsor[s 275joules of heat, has 125joulesof work done on it, and then does 50joules of work, what is the increasein the internal

enerryofthe gas? (A) l0o J (B) 200J

G) 3sor (D) 400J (E) 4s0J

0,-z(11 tr ) - t D-

I,

o e

l,/

l-/

l- _ o (D) e

t

l\ t\ r\ _

o (E)

I

l-l,/ l, /

o

t =4I'J

b'# rA'*^"-W

: w bs

3rwu. Mr 3w'ry^ry

4s

\wn''lv5 q/

a2 (/ t

42.Forcesbetweentrvo obirts which are inverscly

tT

proportional to thc squarcof thc distanceberwecn the ob!rcts include which of thc following? I. Graviational forcc bctweqr rwo oelcstialbodics II. Electrostaticforpc bctwccn two elcctrons III. Nwlear force bctwocntwo neutrons

(A) I only III only I andII only lI andIII only (E) I, I[, andIII

trt

M5-1-rta.. Tz w5-ttt' 45. A block of mass 3m canmove without friction on a

I

horizontal table. This block is atached to another block of mass rz by a cord that passesover a frictionlesspulley, as shown above. If the massesof the cord and the pulley arc negligible,what is the magnitudeof the acoclerationof the desoending block? (Al Tsro

@ sl+ (c) gi3 (D) 2s13 (E) s 43. A particleoscillalesup and down in simple harmonicmotion. Its height / as a function of time , is shownin the diagramabove.At what time t doesthe particle achievcits maximum positive acoeleration? r r A l^ ftt^?a^ lu\rD -rlfoo I t @ (B) 2s (C) 3s (D) 4s (E) Nonc of the above,bccauscthe accclerationis constant 4,4. A wcight lifrcr lifts a mass m at @nstant sp€cdto a height i in time r. What is the averagepow€r output of the weight lifter?

(A) ms

(B) mh (Cl msh (p) msht (Q) nshlt

4 '^

?=* 6' ' 1

,q

A car initially travels north and then turns to the left along a circular curve. This causesa packageon the scat of the car to slide toward the right side of the car. Which of the following is rue of the nct force on the packagewhile it is sliding? (A) The foroe is dirocted away from the centerof the circle. (B) The foroe is dirocted north. (C) There is not enough forcc dirccted north to keep the packagcfrom sliding. @) There is not enough force tangential to the car's path to keep the packagcfrom sliding. (!f There is not enough force directedtoward the centerof the circle to keep the packagefrom sliding.

47. A block of mass rz slideson a horizontal frictionlesstable with an initial s@ u6. It then compresses a springof forceconstant k and is brought to rest.How much is the springcompressed from its natural length?

e

r{*r

Rr

'[,,n\, YLyt

@*

{-ry

Yv''* fli tlf

@T,o

{c)ffw

{z- q," c

6 * VE (E)

The planet Mars hasmass6.4 x lOx kilogramsand radius3.4 x 106meters.The acceleration6f an object in free-fallnear the surfaceof Mars is most nearly (A) zero Q,c= (e'7 rur (B) 1.0m/s2 \z (C) 1.9m/s2 C" tt (t"4'lt\ @y l.z m7s2 -u

: ugr:*? Y(A

(D 9.9m/s2

Lb,L

f i2i>

l"

e

il

r-l-

R2

Serics Conncction

ln,

I 7d"

ffiT

()

Lesst

(F) Less (c) Less (D) L t (E) L /

than I

Greaterthan l, Lessthan tr

{1 tt

'f

(e{.efr'tq

't

y

?4L'ftt\

R2

hrallcl Cormection

In the diagramsabove,resistors.Rland R2arc shownin two differentconnectionsto the same sourc€of emf € that hasno internal resistance. How doesthe power dissipatedby the resistorsin these two casescomparc? (A) lt is greaterfor the seriesconnection. @ It is greaterfor the parallelconnection. (c) It is the samefor both connections. (D) It is differentfor eachconnection,but one must know the valuesof R1and R2to know which is greater. (E) It is different for eachconnection,but one must know the value of € 0oknow which is grcater. 51. The product 2ampercsx 2volts x 2soconds is eqrral1s (A) (9I @) (D) (E)

8 coulombs 8 newtons 8 joules 8 calories 8 newton-amperes

w-v 'b ? , C > W orl1 "r (f

A radar operatesat a wavelengthof 3 centimeters. The frequencyof thesewavesis 49. Rods P and Q are at rest an inertial rcference frame above. Both rods have length ^Liq this frame.A personmovesat a relativistic y direction.Which of the following wc as comparedto Z, observedfor by the person?

tt

(A) l0-roHz (B) It' Hz

(c) 108Hz

(D) 3 x l08Hz l0roHz

c.- b{ a

Sturt = ,63n't 4l.l O b"

53. In the photoeloctric effect,thenlgUimums€of theelectronsemittedby a metalsurfacewhenit is on whichof the illuminatedby lightdcpcnds | \\ following?

I. Intensity orthelight-

try

".YY,'S

^(wuc( riln"'t7 II. Frequencyofthe-light-f IIL Nature of the photoelectrii surface-)r. L ,/.r ) v (A) I only (B) III only (Q I and II only (E II and III only (E) I, I[, and III

57.Two objrxts, of masscs6 and 8 kilograms, are hung

54. Atoms of isotopesof the sameelementcontain the samenumberof @ ptotont but a differentnumberof neutrons (B) electronsbut a differentnumberof protons (C) neutronsbut a different numberof protons (D) neutronsas electrons (E) protonsas neutrons

55. In eachcycleof a C-arnotengine,100joules of heat is abaorbedfrorn the high-lemperaturereservoirand 60 joules is exhaustedto the low-temperaturereservoir. What is the effrciencyof the engine?

6fr) 4oo/o (D ffi% (c) 67% (D) 150% (E) 167%

w--Y/".4

In the Bohr that the quantized can be following ways? (A) An integral tron wavelengths must fit into the rn's circular orbit. (B) Only one elecfion ist in eachpossible electron state. (c) An electronhas a u2. (D) The atom is a small, positively chargednucleusr6rbite$by el.ectr-ons

(E)

higher energystate.

from the cnds of a stick that is 70 centimeterslong and has marks wery l0 oentimeters,as shown above.If the massof the stick is ncgligible,at which of the points indicated should a cord bc attachedif the stick is to rcrnain horizontal whcn suspcnded from the cord?

(A) A (B) B

8

C D (E) E

/Y=o

.\

b ({) =x(") ?:l -'z(

In the Doppler effoct for sound waves,factors that affect the frequeacythat the obeerverhearsinclude which of the following? ", I. The speedofthe source r/ IL The spcedofthe observer 7 III. The loudneesof the.sound (A) I only (!) III only @) I and II only (D) II and III only (E) I, II, and III

6l{3 Qucstions

59. The figure above showstwo wave pulscsthat are approachingeachother. Which of thc following best showsthc shapeof the resultant pulsc whcn the centersofthepulses,points P and 9, coincide?

(s

t--l t__l A plane 5 mctsrs in lcnglh is inclincd at an anglc of 37', as shown above.A block of wcigflt 20 nefions is plaood at the top of the plane and allouredto slide down.

(B)

61. Thc massof the block is most nearly (A) 1.0kg t^)r-il K (B) 1.2kg (Q l.6kg t\h2 (D 2.0 kg

E-B

(E) 2.ske

(D)

cL-

The magnitude of the normal foroe exertedon the block by thc plane is most ncarly

(A)roN (E)

B I?N (D) 20 N (E)33N

Observationsthat indicatc that visible light has a wavelengthmuch shorter than a centimctcr include which of thc following? I. The colorpd pattern seenin a soap bubble IL The color-edpattern seenwhen light passes through a diffraction grating III. The bending of light when it passesfrom one medium to another medium fefic@drA

(A) (p) (p) (D) ie j

I only III onlY I and II only II andIII only r ,II,an dIII'

Xf r\ t **

Kv*-

cl.

/1*

NI; h9, /

,,v

1o{3

63. The work done on thc block by thc gravitational force during thc lmetcr slidc down the plane is most ncarly

(A) 20J

6l (c)

60J EOJ

(D) r00J (E) 130J

^^tr

0,MrJ

Questisns64-66

\Nu +b

'A 0o$!4(

d-

,-r-f'--.

,\

t\

/'\ ta.R

Pr' ,

aa

A ball is thrownandfollowstheparabolicpath shownBbov€.Air friction is negligiblc.Point Q is thehighestpoint on the path. Points P and X arc the samc height abovc the ground.

64. How do thespoeds of theball at thethreepoints co-rnpare? ( A) D r . r e . uR ( B ) un .r e.r p ( C) u o