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State THREE possible factors that should be considered when choosing a suitable adhesive for this specific application - NSC Agricultural Technology - Question 2 - 2022 - Paper 1
Question 2
State THREE possible factors that should be considered when choosing a suitable adhesive for this specific application. State THREE advantages of using a water trou... show full transcript
Worked Solution & Example Answer:State THREE possible factors that should be considered when choosing a suitable adhesive for this specific application - NSC Agricultural Technology - Question 2 - 2022 - Paper 1
Step 1
State THREE possible factors that should be considered when choosing a suitable adhesive for this specific application.
Answer
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Inflammability: The adhesive should not ignite easily to prevent fire hazards during application.
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Heat Resistance: The adhesive must withstand the temperatures expected in the application without failing.
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Cohesion Duration: The time the adhesive remains effective before it degrades should be sufficient for the application.
Step 2
State THREE advantages of using a water trough made of glass fibre rather than steel.
Answer
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Lightness: Glass fibre is significantly lighter than steel, making it easier to handle and install.
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Corrosion Resistance: Glass fibre does not rust, ensuring longevity and reducing maintenance costs compared to steel troughs.
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Moldability: Glass fibre can be formed into various shapes, allowing for customized designs.
Step 3
Name FOUR chemical substances that do NOT have any effect on Teflon.
Answer
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Adhesives / Glue: These typically do not bond with Teflon.
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Greasers: Most lubricants fail to adhere to Teflon surfaces.
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Dyes / Poisons: Chemical dyes do not react or alter the properties of Teflon.
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Paints: They are usually not effective on Teflon surfaces.
Step 4
Give ONE reason why Vesconite is used in dry applications and explain the answer.
Answer
One reason for using Vesconite in dry applications is that it does not require lubricants. This is because it is made from internal lubricated polymers, making it suitable for applications where maintenance would be difficult or where lubrication could attract dirt and debris.
Step 5
State TWO circumstances where Vesconite can be effectively used on a tractor to replace existing metal bushes.
Answer
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Front-axle swivel bushes: Vesconite can reduce wear and tear in these high-movement areas.
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Steering linkage bushes: Its low friction properties make it ideal for components that require smooth operation.
Step 6
State THREE factors that must be taken into consideration when identifying tin for the manufacturing of food cans.
Answer
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Softness: Tin must be soft to allow for easy molding into can shapes.
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Malleability: It should be malleable to withstand pressure during the canning process without breaking.
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Corrosion Resistance: Tin should resist rusting to protect contents from contamination.
Step 7
Step 8
Explain TWO properties of bronze bushes that make them better suited for the use in implements.
Answer
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Corrosion Resistance: Bronze resists corrosion better than many other metals, prolonging the life of the bushes in wet environments.
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Low Friction Properties: Bronze bushings provide smooth operation when paired with components that experience high friction.
Step 9
State THREE influences of manganese on stainless steel.
Answer
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Corrosion Resistance: Manganese enhances the corrosion resistance of stainless steel, making it ideal for harsh environments.
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Toughness: It increases the toughness, making the steel less likely to break under stress.
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Reduction of brittleness: Manganese helps reduce brittleness, improving the overall mechanical properties.
Step 10
Justify the use of brass over copper for the manufacturing of water couplings.
Answer
Use of Brass over Copper
Brass is preferred for making water couplings due to:
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Strength: Brass is generally stronger than copper and can withstand higher pressures.
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Corrosion Resistance: Brass offers better resistance to corrosion and tarnishing, ensuring longevity.
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Machinability: Brass can be machine worked more easily than copper, allowing for precise fittings.
Step 11
Step 12
Step 13
Describe the daily tasks that must be carried out to maintain an electric fence.
Answer
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Clear any vegetation from the fence line: This prevents the fence from short-circuiting.
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Check for damaged or broken wires: Regular inspection helps maintain effectiveness and safety.
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Examine insulators or loose connections: Ensuring connections are tight prevents loss of power.
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Perform regular testing of the energiser's pulse: This ensures the electric fence is functioning correctly.
Step 14
Explain FOUR soil conditions that can have a negative effect on the earth efficiency of an electrical fence.
Answer
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Peat: Retains moisture which can lead to electrical loss.
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Sandy soil: Poor moisture retention, reducing grounding efficiency.
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Gravel: Can disrupt the contact area, leading to less effective grounding.
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Snow or frozen ground: These conditions can inhibit electrical conductivity, reducing the effectiveness of the fence.