COMPETENCY TEST FOR MARKERS PHYSICAL SCIENCES …€¦ · Physical Science P1 8 WCED: Competency...

Physical Science P1 1 WCED: Competency test for markers August 2015

MARKS: 100

TIME: 2½ hours

This question paper consists of 32 pages and 3 data sheets.

(Please hand this question paper and completed answer book to the administrator after completing

the test)

COMPETENCY TEST FOR MARKERS

PHYSICAL SCIENCES (PAPER 1)

AUGUST 2015

NAME: ……………………………………………………………….. SURNAME: ……………………………………………………….

ID No: …………………………………………………………………………………………………………….

INSTITUTION / SCHOOL ..…………….………………………………………………………………………


INSTRUCTIONS AND INFORMATION 1 Write your name in the appropriate spaces on the ANSWER BOOK. 2 This question paper consists of FOUR sections: SECTION A (10) SECTION B (30) SECTION C (15) SECTION D (45) 3 Answer ALL the questions in each section. 4 You may use a non-programmable calculator. 5 You may use appropriate mathematical instruments. 6 Number the answers correctly according to the numbering system used in this

question paper. 7 YOU ARE ADVISED TO USE THE ATTACHED DATA SHEETS. 8 Give brief motivations, discussions, et cetera where required.


SECTION A: Knowledge of content QUESTION 1: MULTIPLE-CHOICE QUESTIONS Four options are provided as possible answers to the following questions. Each question has only ONE correct answer. Choose the answer and write only the letter (A – D) next to the question number (1.1 – 1.5) in the ANSWER BOOK. 1.1 Three identical trailers, A, B and C are being pulled by a tractor. Each trailer

is attached to each other, and the trailer in front is attached to the tractor, by means of identical inextensible ropes. The tension in each rope is labelled T1, T2 and T3 respectively. Trailers A, B and C are carrying two, one and three 50 kg bags of cement respectively. The mass of the ropes and all types of friction can be ignored.

If the tractor-trailer system has a constant uniform acceleration to the right, then the magnitudes of the tensions T1, T2 and T3 in ascending order is:

A T1, T2, T3

B T2, T1, T3 C T3, T2, T1 D T3, T1, T2 (2)

ABC

T1 T2 T3


Charged rod

X Y Z

1.2 Three identical neutral spheres X, Y and Z are placed on insulating stands. Spheres X and Y are touching each other. A rod with a large negative charge is brought close to sphere X. When spheres X and Y are separated, it is found that electrons were transferred from sphere X to sphere Y. Sphere Y is now brought into contact with sphere Z and then separated.

The charge on each sphere after this whole process is…

Charge on X Charge on Y Charge on Z

A negative negative negative

B positive positive positive C negative positive positive D positive negative negative

(2)


1.3 Three resistors RX, RY and RZ are connected to a battery. The resistors are such that RX = RY = ½ RZ. An ammeter is connected between RX and RY and a voltmeter is connected across RZ as shown in the diagram below. The internal resistance of the battery CANNOT be ignored.

Which ONE of the following is correct for the reading on the ammeter and the voltmeter after resistor RY is removed from the circuit?

Ammeter reading Voltmeter reading

A Increases Increases

B Decreases Decreases

C Increases Decreases

D Decreases Increases

(2)

V

RX RY

RZ

A


1.4 Examine the following statements regarding an electric charge placed in a magnetic field.

i The charge must be moving for it to experience a magnetic force.

ii The velocity of the charge must have a component

perpendicular to the direction of the magnetic field, in order to experience a magnetic force.

iii The moving charge will experience a maximum magnetic force

when it moves parallel to the direction of the magnetic field. The correct statement(s) is/are… A i and ii only B i and iii only C ii and iii only D i, ii and iii (2) 1.5 When red light and blue light are successively shone onto the surface of a

certain metal, electrons are ejected from the surface of the metal.

Which ONE of the following is correct for the work function of the metal and the kinetic energy of the photoelectrons when comparing the effects of blue light to red light?

Work function of metal Kinetic Energy of photoelectrons A Remains the same Greater than

B Remains the same Less than

C Greater than Greater than

D Less than Greater than

(2)

TOTAL MARK FOR SECTION A: 10

Blue light Red light


SECTION B: Knowledge of content INSTRUCTIONS 1 Answer Questions 2, 3 and 4 in your ANSWER BOOK. Start each answer on

a new page. 2 Leave ONE line between two sub questions, for example between

QUESTION 2.1 and QUESTION 2.2. 3 Show the formulae and substitutions in ALL calculations. 4 Round off your numerical answers to TWO decimal places.

TOTAL SECTION B: 30

QUESTION 2 (Start on a new page) A block of mass 8 kg is attached to a block of mass of 20 kg by means of a light inextensible string. The 20 kg block is hanging over the top end of a rough inclined plane at a height of 1,2 m above the ground. The inclined plane makes an angle of 35o with the horizontal. A force of 120 N is applied to the 8 kg block parallel to the inclined plane as shown in the diagram below when the blocks are released. The 8 kg block accelerates up the incline while the force is being applied. Ignore the effects of air friction.

At the instant that the 20 kg block strikes the ground, the speed of the 8 kg block is 1,004 m·s-1. 2.1 What is meant by the term kinetic frictional force? (2)

2.2 Calculate the coefficient of kinetic friction for the block-plane combination. (7) 2.3 How would the answer, calculated in QUESTION 2.2, be affected if the

angle of the incline is now decreased to 20o. Answer only INCREASES, DECREASES or REMAINS THE SAME. Give a reason for the answer. (2)

[11]

ground

120 N

35°

20 kg 8 kg

1,2 m


QUESTION 3 (Start on a new page)

A cannon of mass 4 500 kg is bolted to the ground, so that when it fires a cannonball, it recoils by a negligible amount only. The cannon fires a cannonball of mass 50 kg horizontally with an initial velocity of 551 m·s-1. The cannon is then unbolted from the ground and fires an identical cannonball horizontally. Assume that no external forces are acting on the system when the cannon is unbolted.

3.1 Does the conservation of linear momentum apply when the cannon is bolted to the ground while firing the cannonball? Give a reason for the answer. (2)

Assume that the burning gunpowder imparts the same kinetic energy to the cannon-cannonball system, both when the cannon is bolted to the ground and when it is unbolted. 3.2 Calculate the speed of the cannonball fired by the unbolted cannon. (8)

[10] QUESTION 4 (Start on a new page) The siren of a stationary police car emits a sound of frequency 1200 Hz. The police car accelerates uniformly towards a stationary observer. At a certain point, when the police car is already moving, its displacements are measured at regular time intervals. The graph below represents the displacement versus time graph of the police car as it travels towards the stationary observer.

0

Dis

plac

emen

t (m

)

time (s)

60

12

40

1 4

24

2 3 4 5


Q

ground

P

R

1,4 m

4.1 Draw a sketch graph of apparent frequency (fL) versus velocity (vs) of the police car as it is approaching the observer. (2)

4.2 Use the information in the graph to calculate the frequency of the sound

heard by the observer at t = 4 s. Take the speed of sound in air as 345 m·s-1. (7)

[9] TOTAL MARK FOR SECTION B: 30

SECTION C: Developing marking guidelines INSTRUCTIONS: 1 Provide a complete and accurate marking memorandum that will be a good

guide for marking any candidate's answers to QUESTION 5. 2 The following criteria will be used to assess your marking memorandum:

2.1 Your answers to the questions asked are correct. (6)

2.2 There are sufficient alternative answers that cater for the diverse abilities of the candidates. (4)

2.3 Distribution of the allocated marks for each answer is correct. (5)

TOTAL SECTION C: 15 QUESTION 5 The diagram below represents a track PQR. Only section PQ of the track is frictionless. A block of mass 8 kg, travelling at a constant speed at point P, moves up the track to reach point Q with a speed of 2 m·s-1. The block comes to rest at point R, 1,8 s after it passes point Q. The horizontal section QR of the track is 1,4 m above the ground.


5.1 Is mechanical energy conserved as the block slides from point … (Write down only YES or NO)

5.1.1 P to Q? (1) 5.1.2 Q to R? (1) 5.2 Give a reason for the answer to QUESTION 5.1.2 (1) 5.3 Use the law of conservation of mechanical energy to calculate the speed

of the block at point P. (4) 5.4 Name ONE force that does no work on the block during section QR of the

track. (1) 5.5 Calculate the work done by the gravitational force on the block during

section PQ of its motion. (3) 5.6 Calculate the length QR of the track. (3) 5.7 State the work-energy theorem in words. (2) 5.8 Use the work-energy theorem to calculate the work done by the frictional

force on the block as it moves along section QR. (4) [20]

TOTAL MARK FOR SECTION C: 15


SECTION D: Marking questions that learners answered. INSTRUCTIONS: 1 Mark the learners' answers to QUESTIONS 6, 7 and 8 using the Marking

Memorandum provided after QUESTION 8. 2 Alternative answers are not provided to mark all the learners’ answers. 3 From the answers the learners are giving, write down alternative answers that should be added to the Marking Memorandum in order to mark them. 4 Place each tick at the place in the answer where you are crediting the learner. 5 Show the mark awarded for the answer to each sub-question in the block

provided on the right hand side of the page. 6 The degree to which the mark you award compared with the mark that the

learner should really obtain will be assessed. 7 The total mark awarded to you will be 9 x 5 scripts = 45 marks.

TOTAL SECTION D: 45 QUESTION 6 (Start on a new page) A ball is projected vertically upward from the ground and reaches a maximum height of 4,35 m, before falling back down. On its way down, a girl catches the ball at a height of 0,45 m above the ground as shown below. Ignore the effects of air friction.

6.1 Calculate the speed with which the ball was projected upward. (4) 6.2 Calculate the total amount of time that the ball was in the air. (5)

TOTAL MARK FOR SECTION D: 45


6.3 Sketch a position-time graph to represent the motion of the ball from the moment it is projected until it is caught. USE THE GROUND AS THE ZERO POSITION. Indicate the following values on the graph:

• The maximum height the ball reached after being projected • The height at which the ball was caught • The time at which the ball was caught (4) [13]

QUESTION 7

Two spheres R and S carrying charges of +2 nC and -5 nC respectively, are brought into contact for a while and then separated by a small distance. 7.1 Calculate the net charge on each sphere after touching. (2) After R and S have been in contact and separated by a distance of 150 mm, a third sphere T, carrying an excess of 2,5 x 1010 electrons, is now placed near sphere S as shown in the diagram below.

7.2 Calculate the charge on sphere T. (3) 7.3 Calculate the magnitude and direction of the net electrostatic force on

sphere S due to both spheres R and T. (7) [12]

R S

R S T

80 mm 150 mm


QUESTION 8 (Start the question on a new page) In the circuit represented below, the resistance of lamp L is unknown and the internal resistance of the battery is 1,5 Ω. When switch S is closed, the reading on voltmeter V1 decreases by 4,5 V and the reading on voltmeter V2 is 9 V.

Switch S is closed. 8.1 Calculate the resistance of lamp L. (5) 8.2 Calculate the emf of the battery. (5) 8.3 How will the power dissipated by lamp L be affected if the 20 Ω resistor

burns out. Answer only INCREASES, DECREASES or REMAINS THE SAME. Explain the answer. (4) [14]

S

L

V2

V1

20 Ω

30 Ω

1,5 Ω


SECTION D: Marking guidelines to mark learners’ answers Sample answers to Questions 6, 7 and 8 of 5 candidates appear after this memorandum. Detach the sample answers, mark them and hand in with your ANSWER BOOK. Add any additional/alternative answers with its mark allocation in your Answer Book.

QUESTION 6

6.1 Upwards positive/Opwaarts positief

vf 2 = vi

2 + 2a∆x 0 = vi

2 + 2(-9,8)(4,35) vi = 9,23 m·s-1

Upwards negative/Opwaarts negatief

vf 2 = vi

2 + 2a∆x 0 = vi

2 + 2(9,8)(-4,35) vi = - 9,23 m·s-1

= 9,23 m·s-1

(4) 6.2 POSITIVE MARKING FROM QUESTION 6.1 POSITIEWE NASIEN VANAF VRAAG 6.1

OPTION 1/OPSIE 1 Upwards positive/Opwaarts positief Upwardmotion/Opwaartse beweging:

vf = vi + a∆t 0 = 9,23 + (-9,8)∆t ∆t = 0,94 Downwardmotion/ Afwaartse bewegings: ∆y = vi∆t + ½a∆t2 -3,9 = 0 + ½(-9,8)∆t2

∆t = 0,89 s Total time/Totale tyd = 0,94 + 0,89 = 1,83 s

OPTION 1/OPSIE 1 Upwards negative/Opwaarts negatief Upward motion/Opwaartse beweging:

vf = vi + a∆t 0 = -9,23 + 9,8∆t ∆t = 0,94 s Downwardmotion/ Afwaartse beweging: ∆y = vi∆t + ½a∆t2 3,9 = 0 + ½(9,8)∆t2

∆t = 0,89 s Total time/Totale tyd = 0,94 + 0,89 = 1,83 s

OPTION 2/OPSIE 2 Upwards positive/Opwaarts positief Entire motion/Hele beweging ∆y = vi∆t + ½a∆t2 0,45 = 9,23∆t + ½(-9,8)∆t2

∆t = 1,83 s

OPTION 2/OPSIE 2 Upwards negative/Opwaarts negatief Entire motion/Hele beweging ∆y = vi∆t + ½a∆t2 -0,45 = -9,23∆t + ½(9,8)∆t2

∆t = 1,83 s

(5)


6.3 POSITIVE MARKING FROM QUESTION 6.2 POSITIEWE NASIEN VANAF VRAAG 6.2

Upwards positive/Opwaarts positief

Upwardsnegative/Opwaarts negatief

Marking criteria for graph Nasienriglyne vir grafiek

Correct shape shown Korrekte vorm getoon

Maximum height is 4,35 m Maksimum hoogte is 4,35 m

Height at which ball is caught is 0,45 m Hoogte waar die bal gevang is, is 0,45 m

Time at which ball is caught is 1,83 s Tyd waar die bal gevang is, is 1,83 s

(4) [13]

QUESTION 7

7.1 net charge = QR + QS = +2 +(-5) = -1,5 nC (-1,5 x 10-9 C) (2)

7.2 n = e

Q

2,5 x 1010 = Q -1,6 x 10-19 Q = - 4 x 10-9 C

(3)

‐0,45

1,83

‐4,35

0 time (s)

postion (m)

position (m)

time (s)

4,35

0,45

0 1,83

2

2

Accept:

n =

Q = 2,5 x 1010 X 1,6 x 10-9

= 4 x 10-9

QT = - 4 X10-9C


7.3 POSITIVE MARKING FROM QUESTIONS 7.1 AND 7.2 POSITIEWE NASIEN VANAF VRAE 7.1 EN 7.2 FRS = kQRQS

r2 = 9 x 109(1,5 x 10-9)(1,5 x 10-9) (0,15)2 = 9 x 10-7 N to the right/na regs FST = kQSQT r2 = 9 x 109(1,5 x 10-9)(4 x 10-9) (0,08)2 = 8,4375 x 10-6 N to the left/na links Fnet = 8,4375 x 10-6 – 9 x 10-7 = 7,54 x 10-6 N to the left/na links (7) [12]

QUESTION 8 8.1 Vlost = Ir 4,5 = I(1,5) both formulae/beide formules I = 3 A R = V I

= 9 3 = 3 Ω (5)

8.2 POSITIVE MARKING FROM QUESTION 8.1 POSITIEWE NASIEN VANAF VRAAG 8.1

1 1 1 OR/OF Rp = (20)(30)

Rp R1 R2 20 + 30 1 1 = 12 Ω

20 30 Rp = 12 Ω RTOTAL = 3 + 12 = 15 Ω

Emf (ɛ) = I(R + r) = 3(15 + 1,5) = 49,5 V (5)

= +

= +


8.3 DECREASES (Total) resistance will increase and therefore the (total) current will decrease. Considering the formula P = I2R, since the resistance of the lamp is constant, P is directly proportional to I2/P decreases as I decreases NEEM AF Die (totale) weerstand sal toeneem en die (totale) stroom sal afneem. Vanaf die formule P = I 2R, omdat die weerstand van die gloeilamp konstant is, is P direk eweredig aan I 2/ sal P afneem soos I afneem.

(4) [14]

‐


CANDIDATE 1




CANDIDATE 2




CANDIDATE 3




CANDIDATE 4




CANDIDATE 5




DATA FOR PHYSICAL SCIENCES GRADE 12 PAPER 1 (PHYSICS) GEGEWENS VIR FISIESE WETENSKAPPE GRAAD 12 VRAESTEL 1 (FISIKA) TABLE 1: PHYSICAL CONSTANTS/TABEL 1: FISIESE KONSTANTES

NAME/NAAM SYMBOL/SIMBOOL VALUE/WAARDE

Acceleration due to gravity Swaartekragversnelling

g 9,8 m·s-2

Universal gravitational constant Swaartekragkonstante

G 6,67 x 10-11 N·m2·kg-2

Speed of light in a vacuum Spoed van lig in 'n vakuum

c 3,0 x 108 m·s-1

Planck's constant Planck se konstante

h 6,63 x 10-34 J·s

Coulomb's constant Coulomb se konstante

k 9,0 x 109 N·m2·C-2

Charge on electron Lading op elektron

e -1,6 x 10-19 C

Electron mass Elektronmassa

me 9,11 x 10-31 kg

TABLE 2: FORMULAE/TABEL 2: FORMULES MOTION/BEWEGING

tavv if 221

i ta∆tv∆x or/of 2

21

i ta∆tv∆y

xa2vv 2i

2f or/of ya2vv 2

i2

f ∆t2

vv∆x fi

or/of ∆t2

vv∆y fi

FORCE/KRAG

maFnet mvp

if

net

mvmvp

ptF

mgw

221

r

mGmF 2r

GmF

fsmax =µsN

fk =µkN


WORK, ENERGY AND POWER/ARBEID, ENERGIE EN DRYWING

xFW cos mghU or/of mghE P

2mv2

1K or/of 2

k mv2

1E KWnet or/of knet EW

if KKK or/of kikfk EEE

Wnc = ∆K + ∆U OR Wnc = ∆Ek + ∆Ep t

WP

Pave = Fvave

WAVES, SOUND AND LIGHT/GOLWE, KLANK EN LIG

fv f

1T

ss

LL f

vv

vvf

or/of bb

LL f

vv

vvf

hfE

chE

E = Wo + Kmax OR E = Wo + Ek(max)

where/waar

hf E and/en 00 hfW and/en Kmax = mv2max OR Ek(max) = mv2

max

ELECTROSTATICS/ELEKTROSTATIKA

221

r

QkQF

2r

kQE

q

FE

qW

V

n = e

Q OR n = eq

Q


ELECTRIC CIRCUITS/ELEKTRIESE STROOMBANE

I

VR

emf (ε) = I(R + r) emk (ε) = I(R + r)

...RRR 21s

...R

1

R

1

R

1

21p

Iq t

W = Vq W = VI t W= I2R t

W= R∆tV2

∆t

WP

P = VI P = I2R

R

VP

2

ALTERNATING CURRENT/WISSELSTROOM

2max

rms

II /

2maks

wgk

II

2

VV max

rms / 2

VV maks

wgk

rmsrmsaverage VP I / wgkwgkgemiddeld VP I

RP 2rmsaverage I / RP 2

wgkgemiddeld I

R

VP

2rms

average / R

VP

2wgk

gemiddeld

Date post:	10-Jul-2020
Category:	Documents
Upload:	others
View:	25 times
Download:	3 times

COMPETENCY TEST FOR MARKERS PHYSICAL SCIENCES …€¦ · Physical Science P1 8 WCED: Competency...

Documents