NATIONAL SENIOR CERTIFICATE GRADE 12 · GRADE 12 NATIONAL SENIOR CERTIFICATE. ... Answer QUESTION 12.1 on the given GRAPH PAPER and answer ALL the other questions in the ANSWER BOOK

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This question paper consists of 12 pages and 2 data sheets.

TECHNICAL SCIENCES: PHYSICS (P1)

SEPTEMBER 2018

GRADE 12

NATIONAL SENIOR CERTIFICATE

Technical Sciences P1 2 MDE/September 2018 NSC


INSTRUCTIONS AND INFORMATION 1. Write down your name in the appropriate spaces in your ANSWER BOOK. 2. This question paper consists of FOURTEEN questions. Answer QUESTION 12.1 on

the given GRAPH PAPER and answer ALL the other 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 open between two sub questions, for example between

QUESTION 2.1 and QUESTION 2.2. 6. You may use a non-programmable calculator. 7. You may use appropriate mathematical instruments. 8. You are advised to use the attached DATA SHEET. 9. Show ALL formulas and substitutions in ALL calculations. 10. Round off your final numerical answers to TWO decimal places. 11. Provide brief motivations, discussions, etc. where necessary. 12. Write neatly and legibly.



QUESTION 1: Multiple choice questions

Various options are provided as possible answers to the following questions. Choose the answer and write only the letter (A-D) next to the question number (1.1-1.10) on the answer sheet, for example 1.11 E. (Each question has only ONE correct answer.)

1.1 A constant net force works on a trolley. According to Newton's Second Law of Motion, the acceleration of the trolley is ... the mass of the trolley.

A equal to

B independent from

C directly proportional to

D inversely proportional to (2) 1.2 The following diagram shows a racing car, R, which moves in a straight line to

the left.

The driver of the racing car strikes the brake when the car reaches position P. In which direction will the racing engine accelerate?

A

B

C

D

(2) 1.3 A car drives at a constant velocity on a horizontal road. Which one of the

following statements is true? A The forces acting on the car are not balanced. B There are no forces acting on the car. C The resultant force that acts on the car is zero. D There is no frictional force acting on the car. (2)



1.4 Two objects experience an ELASTIC collision in a closed system. Which ONE

of the following combinations of momentum and kinetic energy is correct?

Momentum ... Kinetic energy ...

A is lost stays conserved

B is lost is lost

C stays conserved is lost

D stays conserved stays conserved (2)

1.5 A big truck collides head to head with a small compact car.

During the collision, the size of the force exerted by the ... A truck is larger than the force exerted by the car. B truck is the same as the force exerted by the car. C car is larger than the force exerted by the truck. D truck and the car are in a ratio according to their respective masses. (2) 1.6 An example of a perfectly plastic body is ... A a trampoline. B an elastic band. C art clay D a spring (2) 1.7 Which one of the following concepts is not involved in the viscosity of a

material? A Restoring force B Intermolecular force C Internal friction D Relative speed (2)



1.8 In a continuous liquid at equilibrium, the pressure applied at any point is transmitted equally to other parts of the liquid. This law is known as as ...

A Hooke’s law B Pascal’s law C Faraday’s law D Newton’s law (2) 1.9 The device that uses electrical energy to provide mechanical energy is called

a ... A dynamo B alternator C electric motor D generator (2) 1.10 A bar magnet can be moved towards or away from a solenoid. Which ONE of

the following factors / actions will increase the change on the galvanometer?

A Use a solenoid with a smaller diameter. B Use a solenoid with less coils. C Use a weaker magnet. D Move the bar magnet faster towards or away from a solenoid. (2) [20]



QUESTION 2: Newton’s laws of motion (Start on a new page.) A 5 ton truck (A), pulls a small car (B), with a mass of a 1000 kg, on a horizontal road as shown in the following diagram: When the truck begins to move, it exerts a force of 970 N at its end of the rope. The frictional force on the car is 200 N. 2.1 Draw a labelled free body diagram of all the force exerted on car B. (4) 2.2 Calculate the acceleration of car B. (5) 2.3 Calculate the normal force on car B. (4) 2.4 Calculate the frictional coefficient for car B. (3) [16] QUESTION 3: Momentum (Start on a new page.) The front of modern cars is designed so that in case of a head-to-head collision it will crumble. A car with, a mass of 990 kg, moves at 20 m·s-1 to the right. It collides with a wall and the front of the car crumbles before the car comes to a standstill in 0,16 s 3.1 Calculate the change in momentum on the car. (4) 3.2 Explain why it is important that the front of the car crumbles. Refer to the

relationship between force and time in the following formula: FNET ∝ 1

∆𝑡

(3) [7]



QUESTION 4: Law of the conservation of momentum (Start on a new page.) An empty coal truck moves right at a constant velocity of 5 m·s-1 through a coal loading dock. The truck is loaded with coal as it moves through the loading dock. The mass of the truck is 10 tonnes and the mass of the coal, which is loaded, is 5 x 103 kg. At the start of the loading process, the truck's engine is cut, but it keeps moving.

4.1 Define the concept of conservation of linear momentum. (2) 4.2 Calculate the velocity of the truck after the coal is loaded. (4) 4.3 If it takes 40 s to load the coal, calculate the impulse on the truck. (4) 4.4 Determine by means of calculations whether the collision is elastic or inelastic. (4) [14] QUESTION 5: Work (Start on a new page.) A worker pulls a 50 kg bag of fertiliser for 30 m over a rough surface. A force of 70 N is applied to the bag at an angle of 25°. The frictional force between the bag and the surface is 20 N. 5.1 Calculate the work done by each of the following forces: 5.1.1 Gravitational force (1) 5.1.2 Applied force (3) 5.1.3 Frictional force (2) [6]



QUESTION 6: Energy (Start on a new page.) Cranes are used on building sites to lift heavy materials.

6.1 A piece of metal with a mass of 700 kg is held 4 m above the ground by a crane. Calculate the potential energy that the metal possesses. (3)

6.2 Calculate the weight of the piece of metal. (2) The piece of metal is dropped to the ground. 6.3 Write down the principle of conservation of mechanical energy in words. (2) 6.4 Calculate the velocity at which the 700 kg piece of metal hits the ground. (5) [12] QUESTION 7: Power (Start on a new page.) A powerful race car with a mass of 840 kg has a maximum power output of 550 hp. 7.1 Convert the power of the race car to watt. (2) 7.2 Calculate the work done by the race car engine if the race car is driven at

maximum power for 12 s. (3) [5]



QUESTION 8: Elasticity (Start on a new page.) A wire made of copper has a radius of 3 mm and a length of 3,6 m. The ratio stress to strain is 1,1 x 1011 N.m-2. 8.1 Calculate: 8.1.1 the cross-sectional area of the wire in m2. (The area of a circle is

A = πr2) (3) 8.1.2 the deformation of the wire if stretched 0,6 x 10-3 m. (3) 8.1.3 the stress. (3) 8.1.4 the deforming force which causes this deformation. (3) [12] QUESTION 9: Viscosity (Start on a new page.)

9.1 Provide a complete definition for viscosity. (2) 9.2 What is the relationship between the viscosity of a liquid and an increase in

temperature? (2) 9.3 Use the above label on the oil can and explain what the SAE value for this oil

means. (3) [7]



QUESTION 10: Hydraulics (Start on a new page.) In the hydraulic system shown in the diagram below, an applied force of 240 N is exerted on piston A1 with a surface area of 0,06 m2.

10.1 Calculate the pressure exerted in the liquid. (3) 10.2 If the area of A2 is 0,3 m2, calculate the output force (thrust). (3) 10.3 Calculate the mechanical advantage of the system. (4) [10] QUESTION 11: (Start on a new page.) 11.1 A boy's laptop needs an input voltage of 20 V. If he connects his computer to a

240 V alternating current power source, he must use a suitable transformer. The primary coil of the transformer contains 1 000 turns.

11.1.1 Is this transformer a step-up or step-down transformer? (1) 11.1.2 Calculate the number of turns required on the secondary coil. (3) 11.2 A single circular loop of wire, 12 cm in diameter, is placed in a 0,6 T magnetic

field. It is removed from the magnetic field in 0,04 s. Calculate: 11.2.1 The flux which is linked to this coil. (4) 11.2.2 The average induced emf. (4) [12]



QUESTION 12: Electromagnetism (Start on a new page.) In an experiment with a capacitor, a girl measures the charge stored in the different potential differences. Her results are shown in the following table.

Experiment 1 2 3 4 5

Charge stored (C) 15 30 60 75 90

Potential difference (V) 2 4 8 10 12

12.1 Draw a graph on the attached graph paper of potential difference (on the

x-axis) versus charge stored (on the y-axis). (3) 12.2 Use the information in the graph to calculate the capacitance. (3) 12.3 Name the independent variable in this experiment. (1) [7] QUESTION 13: Electricity (Start on a new page.) Study the energy consumption of the electrical appliances in the following table:

DEVICE SPECIFICATIONS

Mobile cell phone charger 240 V ; 150 mA

Electric kettle 220 V ; 600 W

Television 60 W

Globe (old type) 100 W

Energy-saving light bulb 15 W

Computer 230 V ; 0,5A

Iron 1,4 kW ; 220V

13.1 Define the term power as it relates to electrical circuits. (2) 13.2 Calculate the power requirements of the mobile phone charger. (3) 13.3 Which device has the highest power requirement? (1) 13.4 Calculate the current that the electric kettle will feed from the supply. (3) 13.5 If a unit of electricity costs R1,65 at the applied municipality, calculate how

much it would cost a family if they use the electric kettle for 15 minutes. (4) [13]



QUESTION 14: Electromagnetic induction (Start on a new page.) A coil is turned into a uniform magnetic field. Part XY moves downwards with

respect to the horizontal. The diagram shows the position of the the coil the moment that the it lies parallel to the magnet field in the horizontal plane.

14.1 What type of generator is illustrated? Explain how your answer. (2) 14.2 In which direction does the current flow in the coil? (Y to X or X to Y?) (1) 14.3 Sketch the voltage-to-time graph for the generator for one circulation in

rotation. (3) 14.4 What energy change takes place in electric cars? (1) 14.5 Name two ways that can be used to increase the motor’s torque. (2) [9] TOTAL: 150

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NATIONAL SENIOR CERTIFICATE GRADE 12 · GRADE 12 NATIONAL SENIOR CERTIFICATE. ... Answer QUESTION 12.1 on the given GRAPH PAPER and answer ALL the other questions in the ANSWER BOOK