PREPARATORY EXAMINATION GRADE 12 · 1.8 A capacitor is connected to a battery and an open switch as shown below. When the switch is CLOSED, the capacitor is FULLY CHARGED. Assume

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PREPARATORY EXAMINATION

GRADE 12

TECHNICAL SCIENCES P1

SEPTEMBER 2019

MARKS: 150

TIME: 3 HOURS

This paper consists of 14 pages and 2 information sheets.

Technical Sciences P1 2 FS/September 2019 Grade 12 Prep. Exam.


INSTRUCTIONS AND INFORMATION 1. Write your name and other information in the appropriate spaces on the

ANSWER BOOK. 2. This question paper consists of TEN questions. Answer ALL the questions in

the ANSWER BOOK. 3. Start EACH question on a NEW page in the ANSWER BOOK. 4. Number the answers correctly according to the numbering system used in this

question paper. 5. Leave one line between two sub-questions, for example between QUESTION

2.1 and QUESTION 2.2. 6. You may use a non-programmable pocket calculator. 7. You may use appropriate mathematical instruments. 8. You are advised to use the attached DATA SHEETS. 9. Show ALL formulae and substitutions in ALL calculations. 10. Round off your FINAL numerical answers to a minimum of TWO decimal

places where applicable. 11. Give brief motivations, discussions, et cetera where required. 12. Write neatly and legibly.



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 – 1.10) in the ANSWER BOOK. 1.1 Two horizontal forces, F1 and F2, act on the same object, which is on

a horizontal surface. The resultant force on the object is zero. F1 and F2 have ...

A different magnitudes and opposite directions.

B different magnitudes and the same direction.

C the same magnitude but opposite directions.

D the same magnitude and the same direction. (2) 1.2 Two forces of 100 N each are simultaneously applied to a stationary

crate that is placed on a horizontal surface. One of the forces is horizontal and the other one is applied at an angle θ to the horizontal.

The crate ... A moves at constant velocity to the left. B accelerates to the right. C accelerates to the left. D remains at rest. (2)

F2

F1

100 N θ

100 N



1.3 Two trolleys approach each other on a horizontal floor at the SAME speed. They collide head-on and come to rest after the collision. Ignore the effect of friction. Which ONE of the following statements is INCORRECT?

A The two trolleys have the same mass. B The total momentum remains constant during the collision. C The two trolleys have the same momentum before the collision. D The two trolleys have the same kinetic energy before the collision. (2)

1.4 A ball is dropped from rest from a height h above the ground. The

gravitational force is the ONLY FORCE acting on the ball while it is falling towards the ground. Which ONE of the following quantities REMAINS CONSTANT while the ball is falling? A Velocity B Kinetic energy C Mechanical energy D Gravitational potential energy (2)

1.5 What do we call a force that changes the shape and size of a body? A Compression force B Deforming force C Restoring force D Tension force (2) 1.6 The viscosity of motor oil INCREASES when the ... the oil DECREASES.

A mass of B density of

C pressure on D temperature of (2)



1.7 Force F1 is applied to a piston, with an area A1, in a hydraulic pipeline. Another piston in the same pipeline has an area A2 and this piston can exert a force F2. Which ONE of the following equations is INCORRECT according to Pascal's law?

A 𝐹1𝐴1 = 𝐹2𝐴2

B 𝐹1𝐴2 = 𝐹2𝐴1

C 𝐹1

𝐹2=

𝐴1

𝐴2

D 𝐴2

𝐹2=

𝐴1

𝐹1 (2)

1.8 A capacitor is connected to a battery and an open switch as shown below.

When the switch is CLOSED, the capacitor is FULLY CHARGED. Assume that the AIR surrounding the capacitor has NO CONDUCTING ability.

Which ONE of the following will happen when the battery is removed? A The capacitor remains fully charged. B The capacitor starts to discharge very fast. C The capacitor starts to discharge very slowly. D The capacitance of the capacitor becomes zero. (2)

Battery

S



1.9 Consider the circuit diagram below. Bulbs A, B and C are identical with the same resistance.

Which ONE of the following is correct when the switch is closed?

A IA = IB

B IA > IB

C IA< IB

D 2IA= IB (2)

1.10 The diagram below shows a bar magnet and a stationary coil. The latter

is connected to a galvanometer. The north pole of the magnet is slowly pushed into the coil at point A. Due to this, the needle of the galvanometer deflects slightly to the right.

What will be observed on the galvanometer if the north pole of the magnet is held STATIONARY inside the coil?

A The needle stays in its deflected position.

B The needle deflects further to the right.

C The needle does not deflect at all. D The needle deflects to the left. (2)

[20]

A

B

C S

S N

G

A



QUESTION 2 (Start on a new page) 2.1 Busi always puts her purse on the passenger seat of her car when she

drives to work. One morning she sees that her purse has fallen onto the floor in FRONT of the passenger seat.

2.1.1 Explain, by using physics principles, why Busi's purse has

fallen onto the floor. Ignore any effect of gravity in your explanation. (2)

2.1.2 On which one of Newton's laws did you base your explanation

in QUESTION 2.1.1? (1) 2.2 Two blocks, X and Y, with masses of 5 kg and 3 kg respectively, are

stationary on a rough, horizontal surface. The blocks are connected by a light, inextensible string. When force F, with a magnitude of 25 N and making an angle of 28° with the horizontal, is applied to the 5 kg block, both blocks move to the left.

2.2.1 State Newton's Second Law of Motion in words. (2)

2.2.2 Draw a free-body diagram, with labels, and identify ALL the forces acting on the 3 kg block. (4)

The coefficient of kinetic friction for blocks X and Y are 0,2 and 0,1 respectively.

Calculate the:

2.2.3 Magnitude of the normal force on block X (4)

2.2.4 Magnitude of the acceleration of the system of blocks (Start with a separate equation for each block and subsequently solve them) (6)

2.2.5 Tension in the string (2)

[21]

X

5 kg

Y

3 kg

F

28°



QUESTION 3 (Start on a new page) 3.1 A hunting rifle of 3,6 kg fires a bullet with a mass of 8,4 g. The bullet

leaves the barrel of the rifle at a speed of 914 m·s-1.

3.1.1 When we deal with the principle of the conservation of momentum, we refer to an isolated system. What does isolated system mean? (2)

An explosion like this one that takes place inside the chamber of the rifle, can be considered a special kind of 'collision' in physics.

3.1.2 Calculate the VELOCITY of the rifle at the instant the shot is fired. (4)

3.1.3 Will the MAGNITUDE of the velocity of the rifle be GREATER THAN,

THE SAME AS or LESS, if a HEAVIER bullet is fired at the same velocity with the same rifle? (1)

3.1.4 Is this 'collision' elastic or inelastic? (1)

3.1.5 Give a reason for your answer to QUESTION 3.1.4 and support

your reason with the necessary calculation(s). (4) 3.2 A soccer ball, with a mass of 400 g, moves across a horizontal floor in

a straight line at a speed of 4 m∙s-1. It hits a wall and then it moves in the opposite direction at 3 m∙s-1 directly after the collision. The ball is in contact with the wall for 0,14 s. Calculate the magnitude of force that the wall exerts on the ball. (4)

[16]

3,6 kg 8,4 g

914 m·s-1



QUESTION 4 (Start on a new page) 4.1 The sketch below shows a 1,5 kg block sliding from REST at point A

to point B along a FRICTIONLESS surface. The height at A is 12 m and at B it is 7,5 m. Ignore the effect of air resistance.

4.1.1 State the principle of conservation of mechanical energy in words. (2)

4.1.2 Calculate the speed of the block at B. (5) 4.2 When the block reaches B, it continues to slide along a ROUGH,

HORIZONTAL surface and comes to rest at point C due to a kinetic frictional force of 4,41 N.

4.2.1 Define the term kinetic frictional force. (2)

4.2.2 Is the mechanical energy conserved while the block moves from B to C? Give a reason for your answer. (2)

4.2.3 Calculate the work done on the block by the kinetic frictional force

if the distance between B and C is 2 m. (3) 4.2.4 Calculate the RATE at which work is done on the block by the

kinetic frictional force if it takes the block 5 s to move from B to C. (3) [17]

B

A

12 m 7,5 m

1,5 kg

1,5 kg

B

A

12 m 7,5 m

1,5 kg 1,5 kg

C



QUESTION 5 (Start on a new page)

5.1 One end of a wire, 2 m in length, is attached to the ceiling. It has a cross-sectional area in the form of a circle with a diameter of 3 mm. An 80 kg mass piece is attached to the other end of the wire. Due to this, the length of the wire is increased by 4,4 mm. The mass piece does not touch the floor.

5.1.1 Define the term stress in words. (2)

Calculate the:

5.1.2 Stress on the wire (4)

5.1.3 Strain of the wire (3)

5.1.4 Wire's elasticity modulus (3)

5.2 Write down TWO examples of practically perfectly elastic bodies. (2) [14]

QUESTION 6 (Start on a new page)

The diagram below shows a hydraulic lift. A force F1 of 250 N is exerted on piston 1, which has a circular area A1. The radius of A1 is 2 cm. Piston 2, which is also circular in shape, has an area A2 of 6,158 m2. 6.1 State Pascal's law in words. (2)

6.2 Calculate:

6.2.1 A1 (3)

6.2.2 F2 (3)

6.3 The distance between the two pistons is decreased by using a shorter pipe. How will it affect your answer to QUESTION 6.2.2? Write only INCREASE, DECREASE or REMAIN THE SAME. (2)

6.4 Name TWO uses of hydraulic systems. (2) [12]

F1 = 250 N F2

Piston 2 Piston 1

A2 = 6,158 m2 A1



QUESTION 7 (Start on a new page) A p-n junction is a boundary between two types of semiconductor materials. 7.1 What is the difference between a p-type and an n-type semiconductor? (2) 7.2 Consider circuit diagrams X, Y and Z. The circuit symbols have their usual

meanings.

In which ONE of X, Y or Z is a DIODE connected such that a FORWARD BIASED situation exists? (2)

[4] QUESTION 8 (Start on a new page) The charge on the plates of a capacitor is 2 μC and the potential difference across the capacitor is 10 000 V. 8.1 Define the term capacitor. (2) 8.2 Calculate the capacitance of the capacitor in basic SI units. (4) 8.3 The distance between the plates is 1,5 mm and air is the dielectric

material. Calculate the total SURFACE AREA of the capacitor. (4) 8.4 How does a DECREASE in the DISTANCE between the plates affect the

capacitance if all the other factors remain constant? Choose your answer from INCREASE, REMAIN THE SAME or DECREASE and explain your answer. (2)

8.5 Give ONE example where capacitors are used in the technology. (1)

[13]

Y X Z



QUESTION 9 (Start on a new page) In the circuit diagram below, the battery has an emf of 12 V. Ignore the internal resistance of the battery. 9.1 State Ohm's law in words. (2) 9.2 Calculate the:

9.2.1 Total resistance in the circuit (4)

9.2.2 Reading on the ammeter (3)

9.2.3 Reading on the voltmeter (2)

9.2.4 Power of the 4 Ω resistor (3) 9.3 Will the ammeter reading INCREASE, DECREASE or REMAIN THE

SAME if the 5 Ω resistor is removed? Give a reason for your answer. (2) [16]

5 Ω

A

4 Ω

3 Ω

V



QUESTION 10 (Start on a new page) 10.1 In the diagram below a bar magnet is being pushed into a coil. The direction

of the current in the coil is indicated.

10.1.1 State Faraday's law of electromagnetic induction in words. (2)

10.1.2 What is the polarity of the coil at P while the magnet ENTERS the coil? (1)

10.1.3 How can the deflection on the galvanometer needle be

increased? Name TWO methods. (2) 10.2 A coil, with an area of 2,29 x 10-3 m2, consists of 75 turns. The coil is in a

magnetic field that is perpendicular to the area of the coil. The magnetic flux density is 0,4 T.

10.2.1 Calculate the magnetic flux. (3) 10.2.2 The magnetic FLUX changes TO ZERO during a time interval

of 0,05 s due to the motion of the coil. Calculate the induced emf. (3)

10.3 A transformer has 1 000 turns on the primary coil and 100 turns on the

secondary coil. Calculate the output voltage of this transformer if the primary voltage is 230 V. (3)

G

P

Magnet



10.4 The diagram below represents either an alternating current (AC) generator or a direct current (DC) generator.

10.4.1 What type of energy conversion takes place in a generator? (1) 10.4.2 Is this an AC or DC generator? Give a reason for your answer. (2)

[17]

GRAND TOTAL: 150

Brushes

Technical Sciences P1 FS/September 2019 Grade 12 Prep. Exam


DATA FOR TECHNICAL SCIENCES GRADE 12 PAPER 1

GEGEWENS VIR TEGNIESE WETENSKAPPE GRAAD 12

VRAESTEL 1 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

Permittivity of free space Permittiwiteit van vrye spasie

εo 8,85 x 10-12 F·m-1

TABLE 2: FORMULAE/TABEL 2: FORMULES FORCE/KRAG

maFnet mvp

Nμ=f s

max

s Nμ=f kk

if

net

mv- mv=pΔ

pΔ=tΔF

mgFg

WORK, ENERGY AND POWER/ARBEID, ENERGIE EN DRYWING

xFW cos mghU or/of mghEP

2mv2

1K or/of 2

k mv2

1E Pave = Fvave / Pgemid = Fvgemid

ME = Ek + Ep t

WP

ELASTICITY, VISCOSITY AND HYDRAULICS ELASTISITEIT, VISKOSITEIT EN HIDROULIKA

A

F

L

Δε

Kε

σ

2

2

1

1

A

F

A

F

Technical Sciences P1 FS/September 2019 Grade 12 Prep. Exam

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ELECTROSTATICS/ELEKTROSTATIKA

d

ΑεC

ο

d

VE

V

QC

CURRENT ELECTRICITY/STROOMELEKTRISITEIT

I

VR Iq t

W = VQ W = VI t W = I

2R t

W = R

ΔtV2

Δt

WP

P = VI

R=P 2I

R

VP

2

...RRR 21s

...R

1

R

1

R

1

21p

ELECTROMAGNETISM/ELEKTROMAGNETISME

BA ɛ =Δt

ΔN

p

s

p

s

N

N

V

V

output

N S

Documents

PREPARATORY EXAMINATION GRADE 12 · 1.8 A capacitor is connected to a battery and an open switch as shown below. When the switch is CLOSED, the capacitor is FULLY CHARGED. Assume