AGRICULTURAL TECHNOLOGY
GRADE 12 
AMENDED SCE PAST PAPERS AND MEMOS
MAY/JUNE 2018 2018

INSTRUCTIONS AND INFORMATION 

1. GENERAL INSTRUCTIONS AND INFORMATION
   1.1 This question paper consists of TWO sections, namely SECTION A  and SECTION B.
   1.2 BOTH sections are COMPULSORY.
   1.3 Answer ALL the questions in the ANSWER BOOK.
   1.4 Number the answers correctly according to the numbering system  used in this question paper.
   1.5 You may use a non-programmable calculator.
   1.6 Write neatly and legibly.
2. SECTION A: SHORT QUESTIONS
   2.1 This section consists of THREE questions.
   2.2 Follow the instructions when answering the questions.
3. SECTION B: STRUCTURED LONG QUESTIONS 
   3.1 This section consists of FIVE questions.
   3.2 Start EACH question on a NEW page.

QUESTIONS 

SECTION A 
QUESTION 1 
1.1 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  numbers (1.1.1 to 1.1.10) in the ANSWER BOOK, e.g. 1.1.11 D. 
1.1.1 The … is used to remove welding spatter from metal.  

1. prick punch
2. rasp
3. angle grinder
4. hack saw 

1.1.2 The … is used to remove a bearing from an alternator shaft without  damaging the components.  

1. acetylene flame
2. claw hammer
3. bearing chisel
4. bearing puller 

1.1.3 The ideal number of teeth per 25 mm on a hacksaw blade used to  cut 20 mm solid aluminium bar: 

1. 6 teeth per 25 mm
2. 18 teeth per 25 mm
3. 52 teeth per 25 mm
4. 62 teeth per 25 mm 

1.1.4 … is used for the manufacturing of O rings. 

1. Fibreglass
2. Teflon
3. Perspex
4. Bakelite 

1.1.5 This material should NOT be grinded with a bench grinder because  the material clogs the grinding wheel pores causing the wheel to  overheat: 

1. Cast iron
2. Mild steel
3. Copper
4. Stainless steel

1.1.6 The use of compressed air in the farm workshop is associated with  …  

1. soldering.
2. MIG welding.
3. TIG welding.
4. plasma cutting. 

1.1.7 Incorrect calibration of a diesel pump on a tractor can be identified  by …  

1. black smoke exiting the exhaust.
2. noisy valves. 
3. white smoke exiting the exhaust. 
4. the engine that back-fires. 

1.1.8 Modern technological systems, such as …, are used to notify the  operator when grain is blocking the system in a combine harvester. 

1. yield monitors 
2. flow sensors
3. neutron probes
4. tensiometers 

1.1.9 The drain pipe connecting the toilet to the septic tank is made  from … 

Related Items

1. copper.
2. latex.
3. PVC.
4. iron. 

1.1.10 The most suitable all-purpose fire extinguisher for a welding  workshop: 

1. Foam extinguisher 
2. Water hose 
3. Water extinguisher 
4. Dry powder extinguisher (10 x 2) (20)

1.2 Change the UNDERLINED word(s) in each of the following statements to  make the statements TRUE. Write only the word(s) next to the question  numbers (1.2.1 to 1.2.5) in the ANSWER BOOK, e.g. 1.2.6 Tractor. 
1.2.1 Safety signs attached to an electric fence must be made of plastic  with a red background. 
1.2.2 A newspaper is the most effective type of communication to inform  farm neighbours about an immediate emergency. 
1.2.3 A one-way valve is a device that is capable of adjusting the water  delivering time in response to current environmental conditions. 
1.2.4 Compressed air is used as a hydraulic fluid in a car's bottle jack. 
1.2.5 Steel that has a copper coating produces poisonous gases when  subjected to welding. (5 x 2) (10) 
1.3 Choose a word/term from COLUMN B that matches the description in  COLUMN A. Write down only the letter (A–H) next to the question numbers (1.3.1 to 1.3.5) in the ANSWER BOOK, e.g. 1.3.6 I. 

 (5 x 2) (10)
TOTAL SECTION A: 40

SECTION B 
QUESTION 2: MATERIALS AND STRUCTURES  
(Start this question on a NEW page.) 
2.1 Indicate the alloy metal that is specifically used to manufacture the following  products and give TWO reasons why the metal is used: 
2.1.1 Milk tanks (3)
2.1.2 Fittings for hot-water copper pipes (3)
2.1.3 Hammering tools that can be used in explosive atmospheres (3) 
2.2 Name TWO hot-working processes that can be used to change the structural  properties of brass. (2) 
2.3 Concrete and fibreglass drinking troughs are used to provide water to farm animals. 
2.3.1 Give TWO reasons why farmers would prefer fibreglass troughs instead of concrete troughs for cattle. (2) 
2.3.2 Describe the resin that is used to manufacture fibreglass  products. (2) 
2.3.3 Name TWO methods that can be used to join fibreglass parts. (2) 
2.4 Give FIVE reasons why Vesconite is the best material for the manufacturing  of bushes. (5) 
2.5 Describe how an adhesive should be applied to a surface to ensure sufficient  cohesion. (4)
2.6 An earth return system, as shown in the illustration below, is needed for the  electric fence to function effectively. 

2.6.1 Briefly discuss the procedure that must be followed when testing  the earth system of an electric fence. (4) 
2.6.2 Give TWO examples where electric fences are used on a farm. (2) 
2.6.3 Name THREE alternative energy sources that can be used to  supply energy to an electrical fence. (3) [35]

QUESTION 3: ENERGY 
(Start this question on a NEW page.) 
3.1 The sketch below shows parts of a wind turbine. Identify the TWO parts  labelled A and B and describe the function of EACH.  
(4) 
3.2 The solar hot-water system shown below is used to heat water without using electricity. 

3.2.1 Explain the working of the solar hot-water system shown above. (4)
3.2.2 Name FOUR benefits of using solar energy to heat water. (4)
3.3 A geothermal energy plant is planned for construction in the Northern Cape. 
3.3.1 State TWO geological aspects that should be considered to  determine the location to construct a geothermal energy plant. (2) 
3.3.2 Describe TWO advantages of a geothermal energy plant. (2)
3.4 Bio-energy is widely used as alternative fuel for agricultural machines. 
3.4.1 Name TWO alternative fuels that can be manufactured from plant material. (2) 
3.4.2 Name TWO crops that can be used to produce bio-fuel. (2) [20]

QUESTION 4: SKILLS AND CONSTRUCTION PROCESSES 
(Start this question on a NEW page.) 
4.1 The illustration below shows the nozzle of a MIG welding apparatus.   

4.1.1 Describe the origin and purpose of the shielding gas cloud that forms around the welding area. (3) 
4.1.2 Explain the procedure that must be followed when the feed wire burns onto the copper welding tip. (4) 
4.1.3 Name TWO circumstances that can cause the feed wire to melt onto the welding tip. (2) 
4.1.4 Name THREE causes of cracks forming on the welding bead when  performing MIG welding. (3) 
4.2 Heat has an influence on the amount of shrinking that occurs in a metal during the welding process. 
4.2.1 Describe shrinking as it occurs in a welding joint. (3) 
4.2.2 Make a freehand drawing to illustrate longitudinal angular shrinking  on a welded project. The dimensions of the two flat bar pieces that  must be welded together is 50 mm x 10 mm x 100 mm. 
The following must be included on the drawing: 

• TWO pieces of metal (1) 
• Welding bead (1) 
• Longitudinal angular shrinking (1) 
• Change in the shape of the metals (1) 

4.2.3 State TWO measures that can be taken to prevent metal from  distorting when welding is performed. (2)
4.3 The illustration below shows an oxy-acetylene set. 

4.3.1 Why is the use of sunglasses not recommended when cutting with  the oxy-acetylene set? (2) 
4.3.2 Describe the possible outcome for the gas cylinder if it accidentally topples over. (2) 
4.3.3 Name TWO types of metal that can be cut with an oxy-acetylene  welding set. (2) 
4.4 Give technical advice to a farmer who wants to purchase a plasma cutting  machine for general use on the farm. (2) 
4.5 Name FOUR items of personal protective equipment (PPE) that must be worn when doing plasma cutting. (4) 
4.6 State TWO factors that cause poor cutting performance when using the plasma cutting machine. (2) [35]

QUESTION 5: TOOLS, IMPLEMENTS AND EQUIPMENT  
(Start this question on a NEW page.) 
5.1 Specialisation plays a crucial role in the management of a farm to ensure  success in the agricultural sector.  
5.1.1 Name TWO disadvantages of farm mechanisation. (2)
5.1.2 Give TWO examples of fixed capital on a farm. (2) 
5.2 State TWO functions of a shear bolt used in the drive system of a baling  machine. (2) 
5.3 Label the THREE parts of the clutch assembly, A, B and C, as shown in the  photograph below. 
(3) 
5.4 Is it possible for a vehicle to turn around a bend if the differential is locked?  Explain the answer.  (3) 
5.5 Give TWO advantages of using a bearing in a drive system. 
(2)
5.6 Name TWO benefits of thermoplastic universal joints. (2) 
5.7 Make a neat freehand drawing of a ratchet-type slip clutch and indicate the  following components. 

• Ratchet plate (1) 
• Pressure spring (1) 
• Driven gear with ratchet plate (1) 
• Adjusting nut (1) 

5.8 Explain to a tractor operator why it is better to move heavy loads with the rear  fork lift rather than with the front fork lift, as shown in the picture below. 
(2) 
5.9 Describe what happens when the top link between a tractor and a plough is  removed when ploughing. (2) 
5.10 Name the connection points on the tractor where the quick coupling mechanism shown below should be connected. 
(2)
5.11 Name THREE systems on a combine harvester that must be set or monitored  to limit the loss of maize kernels during the harvesting process. (3) 
5.12 Hammer mills that vibrate will not last long. Name THREE preventative  measures that you must implement to keep a hammer mill from vibrating. (3) 
5.13 Indicate TWO places on a tractor where an automatic depth control  mechanism can be installed. (2) 
5.14 State THREE advantages of using transmission oil in a tractor hydraulic  system. (3) 
5.15 A diesel tank with a surface area of 9 m² needs to be painted. Use a corrosion  preventative paint with a covering capability of 3 m² per litre. TWO coats of  paint are required on the tank. 
Calculate the amount of paint required. (Show ALL calculations) 
 (3) 

[40]

QUESTION 6: WATER MANAGEMENT 
(Start this question on a NEW page.) 
6.1 Complete the table below regarding different irrigation systems. Write only the  answer next to the question numbers (6.1.1 to 6.1.4). 

6.2 State FOUR disadvantages of using a flood irrigation system. (4)
6.3 Name the function of EACH of the following parts of an irrigation system:
6.3.1 Sand filter (1)
6.3.2 Sprinkler (1)
6.3.3 Pump (1)
6.3.4 Solenoid valve (1)
6.3.5 One way valve (1)
6.4 The photographs below show devices used in irrigation scheduling.  

6.4.1 Name devices A and B above. (2)
6.4.2 What is the main purpose of the devices shown above? (1)
6.5 Name TWO devices that are used to control garden watering systems. (2)
6.6 Describe the operation of a septic tank drainage system. (3) 
6.7 Name THREE points to consider when identifying a suitable location for the  installation of a septic tank. (3) 
6.8 Describe the operation of a pipe drainage system. (3) 
6.9 Name THREE types of water purification systems that use a membrane to  purify household water. (3) [30] 

TOTAL SECTION B: 160
GRAND TOTAL: 200