Systems & Control – Key content — Paper 4 · IGCSE Design and Technology 0445

9 (a) Fig. 8 shows a cycle brake lever in the released and pulled position and the brake mechanism. outer cable inner cable brake mechanism brake lever in pulled position Fig. 8 (i) State the order of lever used on the brake lever. … [1] (ii) The brake lever and brake mechanism are connected by a cable. Give two benefits of a cable linkage. 1 … … 2 … … [2] (iii) Give one drawback of a cable linkage. … … [1] (iv) Fig. 9 shows the dimensions of the brake lever and part of the mechanism. 5N 35 cable 110 90 brake block 30 Fig. 9 Calculate the force generated at the brake block by a 5N pulling force at the end of the brake lever. … … … … … [4] (b) Mechanisms require energy to operate; it is often necessary to store the energy before it is used in a mechanism. (i) Use the words below to complete the sentence about the energy conversion that takes place when a battery is used to power a mechanism. light chemical mechanical heat electrical magnetic An electrical battery will convert stored … energy into … energy which is converted by a motor into … energy. [3] (ii) Give two examples of how energy, other than electrical energy, can be stored before it is used in a mechanism. 1 … 2 … [2] (iii) Explain, using an example, how designers can reduce the energy demand of a mechanism. … … … … [3] (c) (i) A ratchet and pawl mechanism will only rotate in one direction. Use sketches and notes to show how a ratchet and pawl mechanism works. [3] (ii) Name one other mechanism that will only rotate in one direction. … [1] (d) (i) Part of the cylinder head of an engine is shown in Fig. 10. rocker shaft rocker valve stem valve spring push rod cylinder head cam follower valve camshaft Fig. 10 The valve opens when the camshaft rotates and lifts the cam follower. Movement is transmitted through the push rod and rocker to the valve stem, opening the valve. The valve spring holds the valve closed until the cam lifts the push rod. Give two ways that a designer could change the distance moved by the valve as it opens. 1 … … 2 … … [2] (ii) State the movement of the rocker as the camshaft rotates. … [1] (e) Fig. 11 shows two screw threads with the same outside diameter. A B Fig. 11 (i) State one difference between the screw threads. … [1] (ii) Give one effect that will be noticed when using thread B compared to thread A. … … [1]

25 marks

Mark scheme: 9(a)(i) Second order / second class lever 1 9(a)(ii) Benefits of a cable could include: • Able to bend / be routed around tubes • High tensile strength • Easily replaced / adjusted • Low cost to replace • Can work over a long distance • Lighter than solid linkage 2 × 1 marks for valid benefits 2 Allow any other valid benefits Allow ‘ instant movement’ 9(a)(iii) Drawback could include: • Cables can stretch • Cables can corrode • Single wire in the cable can break causing friction in the casing 1 mark for valid drawback 1 Allow – cable can break Allow ‘maintenance needed’, cannot transmit compressive force’ 9(a)(iv) Increased force at brake lever 90 × 5 = 35 × load [1] Load = 12.86 N [1] Force at mechanism 110 × 12.857 = 30 × load [1] Final load = 47.14 N[1] 4 Allow ecf from first part of calculation Allow 47 N 4 for correct answer with no working Question Answer Marks Guidance 9(b)(i) An electrical battery will convert stored chemical energy into electrical energy which is converted by a motor into mechanical energy 3 × 1 marks 3 9(b)(ii) Storage systems include: • air receiver tank (pneumatics) • spring • raised weight • stored water (hydroelectric / tidal) • diverted water (water mill) • flywheel 2 × 1 marks 2 Allow other valid examples of stored energy Allow ‘GPE’ and ‘EPE’ Allow ‘steam in boiler’ 9(b)(iii) Examples could include engine design, car, aircraft, boat, white goods, washing machine, tumble dryer, fridge, freezer Factors in reducing energy demand could include: Reduced weight, improved aerodynamics, more rigid materials, and better insulation, reduction of friction, switch mechanism off, use alternative energy source 1 mark for suitable example, 2 marks for explanation with two valid points or one point explained in detail 3 9(c)(i) Ratchet drawing / notes [1] Pawl drawing / notes [1] spring or gravity drop for pawl [1] 3 9(c)(ii) One way mechanism is snail cam [1] 1 Allow worm and wheel 9(d)(i) Greater lift on the cam [1] Change fulcrum position on the rocker – reduce distance from rocker shaft to push rod [1] 2 9(d)(ii) The rocker movement is oscillation 1 Question Answer Marks Guidance 9(e)(i) The difference in the threads could be pitch or thread profile [1] 1 Allow mark for understanding shown 9(e)(ii) The effect when using thread B would be that it must be turned more times to provide the same linear movement as thread A It can also be tightened more effectively and will not work loose as easily 1 mark for valid effect 1 Allow – easier to turn Total: 25

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9 (a) Fig. 8 shows a cycle brake lever in the released and pulled position and the brake mechanism. outer cable inner cable brake mechanism brake lever in pulled position Fig. 8 (i) State the order of lever used on the brake lever. … [1] (ii) The brake lever and brake mechanism are connected by a cable. Give two benefits of a cable linkage. 1 … … 2 … … [2] (iii) Give one drawback of a cable linkage. … … [1] (iv) Fig. 9 shows the dimensions of the brake lever and part of the mechanism. 5N 35 cable 110 90 brake block 30 Fig. 9 Calculate the force generated at the brake block by a 5N pulling force at the end of the brake lever. … … … … … [4] (b) Mechanisms require energy to operate; it is often necessary to store the energy before it is used in a mechanism. (i) Use the words below to complete the sentence about the energy conversion that takes place when a battery is used to power a mechanism. light chemical mechanical heat electrical magnetic An electrical battery will convert stored … energy into … energy which is converted by a motor into … energy. [3] (ii) Give two examples of how energy, other than electrical energy, can be stored before it is used in a mechanism. 1 … 2 … [2] (iii) Explain, using an example, how designers can reduce the energy demand of a mechanism. … … … … [3] (c) (i) A ratchet and pawl mechanism will only rotate in one direction. Use sketches and notes to show how a ratchet and pawl mechanism works. [3] (ii) Name one other mechanism that will only rotate in one direction. … [1] (d) (i) Part of the cylinder head of an engine is shown in Fig. 10. rocker shaft rocker valve stem valve spring push rod cylinder head cam follower valve camshaft Fig. 10 The valve opens when the camshaft rotates and lifts the cam follower. Movement is transmitted through the push rod and rocker to the valve stem, opening the valve. The valve spring holds the valve closed until the cam lifts the push rod. Give two ways that a designer could change the distance moved by the valve as it opens. 1 … … 2 … … [2] (ii) State the movement of the rocker as the camshaft rotates. … [1] (e) Fig. 11 shows two screw threads with the same outside diameter. A B Fig. 11 (i) State one difference between the screw threads. … [1] (ii) Give one effect that will be noticed when using thread B compared to thread A. … … [1]

25 marks

Mark scheme: 9(a)(i) Second order / second class lever 1 9(a)(ii) Benefits of a cable could include: • Able to bend / be routed around tubes • High tensile strength • Easily replaced / adjusted • Low cost to replace • Can work over a long distance • Lighter than solid linkage 2 × 1 marks for valid benefits 2 Allow any other valid benefits Allow ‘ instant movement’ 9(a)(iii) Drawback could include: • Cables can stretch • Cables can corrode • Single wire in the cable can break causing friction in the casing 1 mark for valid drawback 1 Allow – cable can break Allow ‘maintenance needed’, cannot transmit compressive force’ 9(a)(iv) Increased force at brake lever 90 × 5 = 35 × load [1] Load = 12.86 N [1] Force at mechanism 110 × 12.857 = 30 × load [1] Final load = 47.14 N[1] 4 Allow ecf from first part of calculation Allow 47 N 4 for correct answer with no working Question Answer Marks Guidance 9(b)(i) An electrical battery will convert stored chemical energy into electrical energy which is converted by a motor into mechanical energy 3 × 1 marks 3 9(b)(ii) Storage systems include: • air receiver tank (pneumatics) • spring • raised weight • stored water (hydroelectric / tidal) • diverted water (water mill) • flywheel 2 × 1 marks 2 Allow other valid examples of stored energy Allow ‘GPE’ and ‘EPE’ Allow ‘steam in boiler’ 9(b)(iii) Examples could include engine design, car, aircraft, boat, white goods, washing machine, tumble dryer, fridge, freezer Factors in reducing energy demand could include: Reduced weight, improved aerodynamics, more rigid materials, and better insulation, reduction of friction, switch mechanism off, use alternative energy source 1 mark for suitable example, 2 marks for explanation with two valid points or one point explained in detail 3 9(c)(i) Ratchet drawing / notes [1] Pawl drawing / notes [1] spring or gravity drop for pawl [1] 3 9(c)(ii) One way mechanism is snail cam [1] 1 Allow worm and wheel 9(d)(i) Greater lift on the cam [1] Change fulcrum position on the rocker – reduce distance from rocker shaft to push rod [1] 2 9(d)(ii) The rocker movement is oscillation 1 Question Answer Marks Guidance 9(e)(i) The difference in the threads could be pitch or thread profile [1] 1 Allow mark for understanding shown 9(e)(ii) The effect when using thread B would be that it must be turned more times to provide the same linear movement as thread A It can also be tightened more effectively and will not work loose as easily 1 mark for valid effect 1 Allow – easier to turn Total: 25

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11 Power sources used to operate mechanisms usually have safety features that will prevent injury to a user. (a) Complete the table using a suitable safety device for each power source from the list given below. One has been done for you. PTM switch solenoid valve fuse residual current device (RCD) regulator Power Source Safety Device mains electricity natural gas low voltage electricity fuse compressed air [3] (b) Two types of drive system are shown in Fig. 10. 60 t driver 10 t 40 t belt drive geared drive Fig. 10 (i) Describe two outcomes of using the belt drive system shown in Fig. 10. 1 … 2 … [2] (ii) Draw on Fig. 10 to show the direction of rotation of the 10 t gear and the 40 t gear in the geared drive system. [2] (iii) Give two benefits of using a belt drive rather than a geared drive. 1 … 2 … [2] (iv) Explain why drive systems cannot be 100% efficient. … … … … [3] (c) Fig. 11 shows a hand drill. Fig. 11 (i) Name the type of gear used in the hand drill. … [1] (ii) Give two reasons for using this type of gear in the hand drill. 1 … 2 … [2] (iii) State the velocity ratio of the gears used in the hand drill. … [2] (iv) Calculate the speed of the chuck when the handle turns the 56 t gear at 60 rpm. … … … [2] (v) The shaft of the hand drill rotates in plain bearings. Give one drawback of using plain bearings. … [1] (vi) The end of the shaft rotates against a ball bearing. Explain why the ball bearing is needed in this position. … … … … [2] (d) Fig. 12 shows a pair of garden shears with a compound or double lever action. Fig. 12 Calculate the mechanical advantage of the shears if the grass is being cut at the tip of the blade. … … … … … [3]

25 marks

Mark scheme: 11(a) 3 1 mark for each correct. 11(b)(i) The driven pulley will turn anti-clockwise, 1 mark, The speed of the driven pulley will be slower than the driver, 1 mark. 2 11(b)(ii) 1 mark for each arrow correct, 2 × 1 marks. 2 Arrows may be in different positions on the drawing. 11(b)(iii) Benefits of a belt drive could include: • Pulley position is not so critical • Belt can slip to save damage if a shaft is jammed • Lower initial cost and replacement belt cost than gears • Can be quieter in operation than gears • No lubrication required. 2 × 1 marks for valid benefits 2 Allow other valid benefits [1] [1] Power Source Safety Device natural gas compressed air mains electricity low voltage electricity solenoid valve fuse residual current device RCD regulator Question Answer Marks Guidance 11(b)(iv) Explanation should include: • Frictional losses • Energy lost in generation of heat and sound • Poorly fitting parts • Materials that cause losses e.g. belts that stretch or slip on initial start-up. 3 × 1 marks for each point in explanation. 3 Clear explanation with at least two points included, one point being well explained[3] Explanation with up to three points mentioned but no links to consequence of the cause of energy loss , [2] Award two marks for one point well explained. Single point mentioned, [1] 11(c)(i) Bevel gear, 1 mark 1 11(c)(ii) Reasons will include: • It can change the direction of the drive through 90° • Positive drive with no chance of slipping • Suited to large difference in 1number of teeth on the two gears. 2 × 1 marks. 2 Allow other valid reasons e.g. increased speed of driven gear. 11(c)(iii) 12:56 or 6:28 or 3:14 or 1:4.67 Correct numbers 1 mark, correct way around, 1 mark. 2 11(c)(iv) Speed of chuck = (56 / 12) × 60, 1 mark = 280 rpm, 1 mark 2 2 marks for correct answer with no working. Question Answer Marks Guidance 11(c)(v) Problems with plain bearings include: • Shorter working life than other types of bearing • Replacement may not be possible • Not as precise a fit in many cases • Lubrication will be required; other types can be sealed for life. • More friction / heat is generated 1 mark for valid answer. 1 11(c)(vi) The ball bearing absorbs the thrust from the end of the shaft, [1] when the drill bit is pressed onto the work. [1] Friction at the end of the shaft is reduced [1]. 2 Explanation with two points included [2] Explanation with a single point included [1] Allow 2 marks for one point fully explained. 11(d) Mechanical advantage of the first lever is 800 / 75 = 10.66 Mechanical advantage of the second lever is 40 / 220 = 0.18 Combined advantage is 10.66 × 0.18 = 1.94 3 3 marks for correct answer with no working.

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11 Power sources used to operate mechanisms usually have safety features that will prevent injury to a user. (a) Complete the table using a suitable safety device for each power source from the list given below. One has been done for you. PTM switch solenoid valve fuse residual current device (RCD) regulator Power Source Safety Device mains electricity natural gas low voltage electricity fuse compressed air [3] (b) Two types of drive system are shown in Fig. 10. 60 t driver 10 t 40 t belt drive geared drive Fig. 10 (i) Describe two outcomes of using the belt drive system shown in Fig. 10. 1 … 2 … [2] (ii) Draw on Fig. 10 to show the direction of rotation of the 10 t gear and the 40 t gear in the geared drive system. [2] (iii) Give two benefits of using a belt drive rather than a geared drive. 1 … 2 … [2] (iv) Explain why drive systems cannot be 100% efficient. … … … … [3] (c) Fig. 11 shows a hand drill. Fig. 11 (i) Name the type of gear used in the hand drill. … [1] (ii) Give two reasons for using this type of gear in the hand drill. 1 … 2 … [2] (iii) State the velocity ratio of the gears used in the hand drill. … [2] (iv) Calculate the speed of the chuck when the handle turns the 56 t gear at 60 rpm. … … … [2] (v) The shaft of the hand drill rotates in plain bearings. Give one drawback of using plain bearings. … [1] (vi) The end of the shaft rotates against a ball bearing. Explain why the ball bearing is needed in this position. … … … … [2] (d) Fig. 12 shows a pair of garden shears with a compound or double lever action. Fig. 12 Calculate the mechanical advantage of the shears if the grass is being cut at the tip of the blade. … … … … … [3]

25 marks

Mark scheme: 11(a) 3 1 mark for each correct. 11(b)(i) The driven pulley will turn anti-clockwise, 1 mark, The speed of the driven pulley will be slower than the driver, 1 mark. 2 11(b)(ii) 1 mark for each arrow correct, 2 × 1 marks. 2 Arrows may be in different positions on the drawing. 11(b)(iii) Benefits of a belt drive could include: • Pulley position is not so critical • Belt can slip to save damage if a shaft is jammed • Lower initial cost and replacement belt cost than gears • Can be quieter in operation than gears • No lubrication required. 2 × 1 marks for valid benefits 2 Allow other valid benefits [1] [1] Power Source Safety Device natural gas compressed air mains electricity low voltage electricity solenoid valve fuse residual current device RCD regulator Question Answer Marks Guidance 11(b)(iv) Explanation should include: • Frictional losses • Energy lost in generation of heat and sound • Poorly fitting parts • Materials that cause losses e.g. belts that stretch or slip on initial start-up. 3 × 1 marks for each point in explanation. 3 Clear explanation with at least two points included, one point being well explained[3] Explanation with up to three points mentioned but no links to consequence of the cause of energy loss , [2] Award two marks for one point well explained. Single point mentioned, [1] 11(c)(i) Bevel gear, 1 mark 1 11(c)(ii) Reasons will include: • It can change the direction of the drive through 90° • Positive drive with no chance of slipping • Suited to large difference in 1number of teeth on the two gears. 2 × 1 marks. 2 Allow other valid reasons e.g. increased speed of driven gear. 11(c)(iii) 12:56 or 6:28 or 3:14 or 1:4.67 Correct numbers 1 mark, correct way around, 1 mark. 2 11(c)(iv) Speed of chuck = (56 / 12) × 60, 1 mark = 280 rpm, 1 mark 2 2 marks for correct answer with no working. Question Answer Marks Guidance 11(c)(v) Problems with plain bearings include: • Shorter working life than other types of bearing • Replacement may not be possible • Not as precise a fit in many cases • Lubrication will be required; other types can be sealed for life. • More friction / heat is generated 1 mark for valid answer. 1 11(c)(vi) The ball bearing absorbs the thrust from the end of the shaft, [1] when the drill bit is pressed onto the work. [1] Friction at the end of the shaft is reduced [1]. 2 Explanation with two points included [2] Explanation with a single point included [1] Allow 2 marks for one point fully explained. 11(d) Mechanical advantage of the first lever is 800 / 75 = 10.66 Mechanical advantage of the second lever is 40 / 220 = 0.18 Combined advantage is 10.66 × 0.18 = 1.94 3 3 marks for correct answer with no working.

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1 Fig. 1 shows safety symbols that could be found in a workshop. Fig. 1 State the meaning of each symbol. A … B … C … [3]

3 marks

Mark scheme: 1 A – Eye protection to be worn B – Danger Electricity C – Emergency stop button 1 mark for each correct. 3

This question in 0445/41 May/June 2019

2 Give one example of each of the energy sources named below. Renewable energy … Fossil fuel … [2]

2 marks

Mark scheme: 2 Renewable energy – Solar, wind, wave, tidal, geothermal, hydro-electrical, 1 mark Fossil fuel – Coal, gas, oil, 1 mark. 2 For fossil fuel allow any derivatives e.g. diesel, petrol

This question in 0445/41 May/June 2019

1 (a) Name two machines used in manufacturing that can be controlled by a computer. 1 … 2 … [2] (b) Give two benefits of using CAM in batch production. 1 … … 2 … … [2]

4 marks

Mark scheme: 1(a) Lathe, milling machine, router, drill, 3D printer, laser cutter. 2 × 1 marks for suitable machines. 2 Allow any other suitable machines. 1(b) • CAM will allow machine operations to be programmed so repeatable process • Flexible as item being made can quickly be changed • Increased accuracy • Reduced labour cost, one operator can look after many machines. 2 × 1 marks for suitable benefits. 2 Allow marks for any other valid benefits. Allow reference to speed of production 1 mark for each correct, maximum 3

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2 (a) Fig. 1 shows a block diagram for the system used in a tumble drier. door microswitch drying control unit heater clothes complete power moisture sensor Fig. 1 On the list below draw lines from the item to the part it plays in the system. Item Part played in the system door microswitch process control unit output moisture sensor input drying complete feedback [3] (b) Fig. 2 shows a microswitch suitable for use as a sensor on the door of the tumble drier. door C NC NO Fig. 2 Draw lines on Fig. 2 from the wires to the switch terminals to allow an electrical connection between the two wires when the door is closed. [2] (c) Explain why the door microswitch is needed on the tumble drier. … … … [2]

7 marks

Mark scheme: 2(a) 3 marks. 2(b) Connection to C 1 mark. Connection to NO, 1 mark. 2 No marks if more than two connections are made. 2(c) To sense when the door is closed [1] ensuring that the machine cannot start with the door open. [1] 2 2 marks for a clear explanation of single point. door microswitch control unit moisture sensor drying completed process output input feedback C NO NC

This question in 0445/42 May/June 2019

1 Fig. 1 shows safety symbols that could be found in a workshop. Fig. 1 State the meaning of each symbol. A … B … C … [3]

3 marks

Mark scheme: 1 A – Eye protection to be worn B – Danger Electricity C – Emergency stop button 1 mark for each correct. 3

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2 Give one example of each of the energy sources named below. Renewable energy … Fossil fuel … [2]

2 marks

Mark scheme: 2 Renewable energy – Solar, wind, wave, tidal, geothermal, hydro-electrical, 1 mark Fossil fuel – Coal, gas, oil, 1 mark. 2 For fossil fuel allow any derivatives e.g. diesel, petrol

This question in 0445/43 May/June 2019

1 Models are often used when designing a structure. Models can be manufactured or they can be computer generated. (a) Give two benefits of using a manufactured model. 1 … 2 … [2] (b) Give two benefits of using a computer generated model. 1 … 2 … [2] (c) State one other use for a computer in manufacturing. … [1]

5 marks

Mark scheme: 1(a) Benefits of using a model could include: • Can be tested • View all-round the model • Dimensions / proportions can be checked • Different materials can be tried • Shows more than a drawing • Easier for a client to understand 2 × 1 marks 2 Accept any other valid benefit 1(b) Benefits of a computer model could include: • Can be viewed three dimensionally • Accurate testing can be carried out quickly • Variables can be changed quickly E.g. dimensions of components • Model can be sent to other people easily • Can be stored easily / does not take up physical space • No cost for materials involved 2 × 1 marks 2 Accept any other valid benefit Reference to speed must be justified 1(c) Other uses include: • Stock control • CAD / CAM • Quality control • Internet research 1 mark for suitable use 1 Accept any other valid use

This question in 0445/41 Oct/Nov 2019

1 Models are often used when designing a structure. Models can be manufactured or they can be computer generated. (a) Give two benefits of using a manufactured model. 1 … 2 … [2] (b) Give two benefits of using a computer generated model. 1 … 2 … [2] (c) State one other use for a computer in manufacturing. … [1]

5 marks

Mark scheme: 1(a) Benefits of using a model could include: • Can be tested • View all-round the model • Dimensions / proportions can be checked • Different materials can be tried • Shows more than a drawing • Easier for a client to understand 2 × 1 marks 2 Accept any other valid benefit 1(b) Benefits of a computer model could include: • Can be viewed three dimensionally • Accurate testing can be carried out quickly • Variables can be changed quickly E.g. dimensions of components • Model can be sent to other people easily • Can be stored easily / does not take up physical space • No cost for materials involved 2 × 1 marks 2 Accept any other valid benefit Reference to speed must be justified 1(c) Other uses include: • Stock control • CAD / CAM • Quality control • Internet research 1 mark for suitable use 1 Accept any other valid use

This question in 0445/42 Oct/Nov 2019

1 Models are often used when designing a structure. Models can be manufactured or they can be computer generated. (a) Give two benefits of using a manufactured model. 1 … 2 … [2] (b) Give two benefits of using a computer generated model. 1 … 2 … [2] (c) State one other use for a computer in manufacturing. … [1]

5 marks

Mark scheme: 1(a) Benefits of using a model could include: • Can be tested • View all-round the model • Dimensions / proportions can be checked • Different materials can be tried • Shows more than a drawing • Easier for a client to understand 2 × 1 marks 2 Accept any other valid benefit 1(b) Benefits of a computer model could include: • Can be viewed three dimensionally • Accurate testing can be carried out quickly • Variables can be changed quickly E.g. dimensions of components • Model can be sent to other people easily • Can be stored easily / does not take up physical space • No cost for materials involved 2 × 1 marks 2 Accept any other valid benefit Reference to speed must be justified 1(c) Other uses include: • Stock control • CAD / CAM • Quality control • Internet research 1 mark for suitable use 1 Accept any other valid use

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9 Fig. 9.1 shows an outline block diagram of a control system. input output Fig. 9.1 Add labels to complete Fig. 9.1. [2]

2 marks

Mark scheme: 9 [1] 2 input process / control output [1] feedback 2 × 1 mark. Section B

This question in 0445/42 May/June 2020

1 Circle two infinite energy sources from the list below. coal wind oil solar natural gas [2]

2 marks

Mark scheme: 1 coal wind oil solar natural gas 1 mark for each correct. 2 No marks if more than two are circled.

This question in 0445/42 Oct/Nov 2020

2 (a) State one advantage of using CAD/CAM in batch production. … … [1] (b) Name one manufacturing machine that can be controlled by a computer. … [1]

2 marks

Mark scheme: 2(a) Advantages of CAD/CAM in batch production could be: • Repeatability • Reduced set-up time • Accuracy • Reduced labour costs. 1 mark. 1 Allow any other valid alternative ‘Quicker’, ‘easier’, ‘cheaper’, ‘reliable’ must be justified for a mark. 2(b) Any CNC machine, lathe, milling machine router, laser cutter, drill, vinyl cutter, 3D printer, 1 mark. 1 Allow any other valid alternative.

This question in 0445/42 Oct/Nov 2020

1 Circle two infinite energy sources from the list below. coal wind oil solar natural gas [2]

2 marks

Mark scheme: 1 coal wind oil solar natural gas 1 mark for each correct. 2 No marks if more than two are circled.

This question in 0445/43 Oct/Nov 2020

2 (a) State one advantage of using CAD/CAM in batch production. … … [1] (b) Name one manufacturing machine that can be controlled by a computer. … [1]

2 marks

Mark scheme: 2(a) Advantages of CAD/CAM in batch production could be: • Repeatability • Reduced set-up time • Accuracy • Reduced labour costs. 1 mark. 1 Allow any other valid alternative ‘Quicker’, ‘easier’, ‘cheaper’, ‘reliable’ must be justified for a mark. 2(b) Any CNC machine, lathe, milling machine router, laser cutter, drill, vinyl cutter, 3D printer, 1 mark. 1 Allow any other valid alternative.

This question in 0445/43 Oct/Nov 2020

1 Identify two renewable energy sources from the list below. oil solar natural gas nuclear hydroelectric 1 … 2 … [2]

2 marks

Mark scheme: 1 Solar, 1 mark. Hydroelectric, 1 mark. 2

This question in 0445/42 May/June 2021

2 (a) Give one example of a manufacturing machine that can be controlled by computer. … [1] (b) Describe two benefits of using computer controlled machines. … … … … [2]

3 marks

Mark scheme: 2(a) Computer controlled machines will include: • Lathe • Milling machine • Router • Vinyl cutter or 3D printer • Engraver • Laser cutter 1 mark for valid CNC machine. 1 Allow mark for any other valid alternative. 2(b) Benefits will include: • Accuracy • Storage of program for individual items • Repeatability • Can be operated directly from CAD design. • Reduced workforce 2 × 1 marks. 2 Allow other valid benefits

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3 Fig. 3.1 shows block diagrams of two types of control system. system A system B Fig. 3.1 Use examples to explain the differences between the two types of control system. … … … … … [3]

3 marks

Mark scheme: 3 Example of an open loop system for system A, [1] Example of a closed loop system for system B, [1] Understanding of the part played by feedback in a closed loop system, [1]. 3

This question in 0445/42 May/June 2021

6 Fig. 6.1 shows a safety symbol for an item of personal protective equipment (PPE). Fig. 6.1 State the meaning of the safety symbol. … … [1]

1 marks

Mark scheme: 6 Ear protection / ear defenders should be worn, 1 mark. 1

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5 Fig. 5.1 shows a hand held moisture meter for testing moisture content in wood. softwood board hand held moisture meter meter in use on softwood Fig. 5.1 Give two ergonomic features that have been considered in the design of the hand held moisture meter. 1 … 2 … [2]

2 marks

Mark scheme: 5 Ergonomic features could be: • Handle shaped to fit hand • Different material for grip • Rounded surface with no sharp edges means comfortable grip • Clear display, large numbers • Buttons easily reached when holding • Bar graph display as well as digital readout. 2 2 × 1 mark for two features mentioned. Allow two marks for one feature fully described.

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6 Describe the purpose of a specification when designing and making. … … … [2]

2 marks

Mark scheme: 6 Purpose of a specification could be: • To identify the features required in a design • To provided instructions to a designer • To measure initial ideas against • When evaluating completed product. 2 Allow other valid uses of the specification. 2 × 1 mark for two purposes mentioned. Allow two marks for one purpose fully described.

This question in 0445/43 May/June 2021

7 Give two benefits of using a CNC machine for manufacturing a batch of products. 1 … … 2 … … [2]

2 marks

Mark scheme: 7 Benefits will include • Accuracy • Repeatability • Rapid production • Quick change from one product to another • Program can be modified easily • Decrease in labour needed. 2 × 1 mark 2 Allow other valid reasons

This question in 0445/43 May/June 2021

10 (a) Fig. 10.1 shows a 27 m high structure used to support an illuminated star. Fig. 10.1 (i) Name two stationary and two moving loads that will affect the stability of the structure. Stationary Loads 1 … 2 … Moving Loads 1 … 2 … [4] (ii) Ties and struts are used to keep the illuminated star structure rigid. State one force resisted by a tie and one force resisted by a strut. Tie … Strut … [2] (iii) Give one advantage and one disadvantage of using struts, rather than ties in the structure. Advantage … Disadvantage … [2] (b) Fig. 10.2 shows part of a structure that has been joined using three bolts and nuts. steel strip 70 x 10 3 x M10 bolts x 30 long Fig. 10.2 (i) Explain why more than one bolt is required in the joint. … … … … [2] (ii) When the nut is fully tight, the 30 mm length of bolt passing through the plate has stretched to 30.1 mm. Calculate the strain in the bolt. change in length Use the formula: Strain = original length … … … … [2] (iii) Explain how torsion and shear could affect the bolt and its threads if the nut is over-tightened. … … … … … [4] (iv) Give two possible reasons for joining the materials with bolts and nuts rather than welding the materials together. 1 … 2 … [2] (c) Fig. 10.3 shows two methods of extending the length of a wooden beam. Method A − cut joint with reinforcing bolts Method B − beam ends cut square with bolted plates either side Fig. 10.3 (i) Give one reason why extending a wooden beam may be necessary. … [1] (ii) Describe one advantage of method B when compared to method A. … … … [2] (iii) Laminating is another way of making a long beam. Use sketches and notes to show a laminated beam. [2] (d) Fig. 10.4 shows a playground see-saw mounted on a hard rubber spring. hard rubber spring Fig. 10.4 Explain why the see-saw may not be in a state of equilibrium when it is in use. … … … [2]

25 marks

Mark scheme: 10(a)(i) Stationary loads will include: • Material used in the supporting structure • Star • Lighting on the star Moving loads will include: • Wind • Snow / ice / rain • Construction / maintenance workers on the structure 2 × 2 marks 4 Allow other valid responses for either type of load. 10(a)(ii) A tie will resist tension, 1 mark A strut will resist compression, bending and torsion, 1 mark 2 Allow a single resisted force for strut. 10(a)(iii) Advantage – a strut will resist different types of force, whereas a tie will only resist tension, 1 mark. Disadvantage – increased weight in the structure as a result of using struts The material for a strut is likely to be more expensive than a tie, 1 mark. 2 Question Answer Marks Guidance 10(b)(i) • A single bolt will allow the joint to rotate • At least two bolts are needed to prevent this • To overcome failure of a single bolt • Three bolts are more likely to provide accurate alignment. 2 Two points mentioned for 2 marks. Allow 2 marks for a single point fully explained. 10(b)(ii) Change in length is 0.1 mm,1 mark Strain = 0.1 / 30 = 0.003, 1 mark 2 Award both marks if correct answer is given with no evidence of working. 10(b)(iii) Torsion will cause the bolt to turn with the possibility of the bolt failing. This will only occur if the bolt is over-tightened, in which case the head of the bolt will break away from the body. Shear force will be applied to the threads on the bolt causing the threads to break away. 2 × 2 marks. 4 1 mark for a single point recognised for each force. 2 marks if the response is justified. 10(b)(iv) Reasons for using bolts and nuts could include: • Possible need to disassemble the structure • Ease of transport to site • No chance of distortion of the materials • Different materials / non-metals being joined • Three bolts will spread the load across full width of joint • Fine adjustments to position can be made before final tightening. 2 2 marks for two points given in description. Allow 2 marks for a single point fully justified. 10(c)(i) The span needed is greater than the length of timber available. Access to position of beam may be limited, 1 mark for either point 1 10(c)(ii) Advantages of method B include • No complex cutting and fitting of joint • Plates at side give lateral stability and increased strength • More bolts used that will spread the load. 2 Allow 2 marks for fully justified response. Allow 1 mark for a single mentioned Allow reference to comparative strength of the joints 10(c)(iii) Sketch to show at least three layers of ‘beam width’ laminates, 1 mark Joints at ends of laminate staggered, 1 mark 2 Question Answer Marks Guidance 10(d) • The purpose of the see-saw is to allow two users to rise and fall • The movement of users means that it is not in equilibrium • Different weights of user may mean that it is in equilibrium at the extent of its travel. • Hard rubber spring will generate movement 2 Recognition that it is the users who cause movement and loss of equilibrium, 1 mark. Recognition of effect of imbalance in weight of users, 1 mark.

This question in 0445/43 May/June 2021

3 Table 3.1 shows different resistant materials and properties. Complete the table to identify the missing materials and properties. Table 3.1 Material Property concrete … renewable resource … will corrode in damp conditions … plastics … [4]

4 marks

Mark scheme: 3 Property of concrete could be: • resists compression well • long lasting / durable • relatively low cost, 1 mark . Wood / timber is a renewable resource, 1 mark. Steel / iron will corrode in damp conditions, 1 mark. Property of plastics could be: • Easy to form / mould • Can be difficult to recycle / many types can be recycled • Good insulator of heat / electricity • Self-coloured no finish needed, 1 mark. 4 Allow other valid responses in each case. Must be a named resistant metal that will corrode for the mark. Allow ‘lightweight for plastics’ Allow ‘plastics don’t corrode’

This question in 0445/42 Oct/Nov 2021

3 Products can be designed and manufactured so that they can be disassembled. Describe two benefits of being able to disassemble a product after manufacture. 1 … … 2 … … [2]

2 marks

Mark scheme: 3 Benefits of ability to disassemble products will include:  Ability to repair and replace parts  Ease of transport  Ease of storage  Ease of packaging  Product can be modified  Different materials / parts can be separated for recycling and reuse. 2  1 marks.

This question in 0445/42 May/June 2022

5 Describe, using one example, how computers can be used by a manufacturer to increase efficiency in stock control. … … … … [3]

3 marks

Mark scheme: 5 Examples will include:  Keeping inventories  Bar codes / QR codes / RFID to track parts  Online ordering of parts Relevant example, [1]. How it is used by the manufacturer, [1]. How efficiency is increased, [1]. 3 Examples must relate to stock control

This question in 0445/42 May/June 2022

3 (a) Give two benefits of using CAD/CAM in batch production. 1 … … 2 … … [2] (b) Give two drawbacks of using CAD/CAM for one-off production. 1 … … 2 … … [2]

4 marks

Mark scheme: 3(a) Any two benefits such as: Accuracy [1] Repeatability / reduced waste material [1] Rapid change in item being produced / greater productivity [1] Fast transport of data to manufacturing facility / machine [1] Reduced workforce / 24/7 production [1] 3(b) Any 2 drawbacks for one-off production such as: Expense of machinery [1] Setting up time increased [1] Skilled workforce needed for setting up machines [1] Skilled workforce needed for producing drawings [1] 2 Allow any valid drawback

This question in 0445/41 May/June 2023

1 Identify two fossil fuels from the list below. coal geothermal hydroelectric natural gas solar 1 … 2 … [2]

2 marks

Mark scheme: 1 Coal [1] Natural gas [1] 2

This question in 0445/42 May/June 2023

2 Give two reasons why many products are designed with a limited lifetime. 1 … … 2 … … [2]

2 marks

Mark scheme: 2 Any 2 reasons such as: To maintain an ongoing need for the product [1] To make use of new technology [1] To cut costs [1] Reduce ongoing need for spare parts [1]

This question in 0445/42 May/June 2023

3 (a) Give two benefits of using CAD/CAM in batch production. 1 … … 2 … … [2] (b) Give two drawbacks of using CAD/CAM for one-off production. 1 … … 2 … … [2]

4 marks

Mark scheme: 3(a) Any two benefits such as: Accuracy [1] Repeatability / reduced waste material [1] Rapid change in item being produced / greater productivity [1] Fast transport of data to manufacturing facility / machine [1] Reduced workforce / 24/7 production [1] 3(b) Any 2 drawbacks for one-off production such as: Expense of machinery [1] Setting up time increased [1] Skilled workforce needed for setting up machines [1] Skilled workforce needed for producing drawings [1] 2 Allow any valid drawback

This question in 0445/43 May/June 2023

2 Give two items of Personal Protective Equipment (PPE) that should be used on the building site. 1 … … 2 … … [2]

2 marks

Mark scheme: 2 Items of PPE will include: 2 Allow other valid items. • Hard hat • visors / face shield / goggles • Safety boots • High visibility clothing • Dust mask / respirator • Ear defenders • Gloves [2  1]

This question in 0445/41 Oct/Nov 2023

2 Give two items of Personal Protective Equipment (PPE) that should be used on the building site. 1 … … 2 … … [2]

2 marks

Mark scheme: 2 Items of PPE will include: 2 Allow other valid items. • Hard hat • visors / face shield / goggles • Safety boots • High visibility clothing • Dust mask / respirator • Ear defenders • Gloves [2  1]

This question in 0445/42 Oct/Nov 2023

2 Give two items of Personal Protective Equipment (PPE) that should be used on the building site. 1 … … 2 … … [2]

2 marks

Mark scheme: 2 Items of PPE will include: 2 Allow other valid items. • Hard hat • visors / face shield / goggles • Safety boots • High visibility clothing • Dust mask / respirator • Ear defenders • Gloves [2  1]

This question in 0445/43 Oct/Nov 2023

6 Fig. 6.1 shows three safety symbols that may be found in a workshop. A B C Fig. 6.1 State the meaning of each safety symbol. A … B … C … [3]

3 marks

Mark scheme: 6 A – Face covering should be worn [1] B – Face shield should be worn [1] C – Ear protection should be worn [1] 3 Allow marks if reason for using device is given.

This question in 0445/41 May/June 2024

6 Fig. 6.1 shows three safety symbols that may be found in a workshop. A B C Fig. 6.1 State the meaning of each safety symbol. A … B … C … [3]

3 marks

Mark scheme: 6 A – Face covering should be worn [1] B – Face shield should be worn [1] C – Ear protection should be worn [1] 3 Allow marks if reason for using device is given.

This question in 0445/43 May/June 2024

3 Give two reasons why products that can be disassembled are good for the environment. 1 … 2 … [2]

2 marks

Mark scheme: 3 Reasons for disassembly will include: access for repair, ease of recycling, 2 Allow any other valid reasons. more chance to reuse components, reduced cost of disposal, to take up less space [2  1]

This question in 0445/41 Oct/Nov 2024

3 Give two reasons why products that can be disassembled are good for the environment. 1 … 2 … [2]

2 marks

Mark scheme: 3 Reasons for disassembly will include: access for repair, ease of recycling, 2 Allow any other valid reasons. more chance to reuse components, reduced cost of disposal, to take up less space [2  1]

This question in 0445/42 Oct/Nov 2024

3 Give two reasons why products that can be disassembled are good for the environment. 1 … 2 … [2]

2 marks

Mark scheme: 3 Reasons for disassembly will include: access for repair, ease of recycling, 2 Allow any other valid reasons. more chance to reuse components, reduced cost of disposal, to take up less space [2  1]

This question in 0445/43 Oct/Nov 2024

1 (a) Name two fossil fuels. 1 … 2 … [2] (b) Explain how solar energy can be used to provide power at night. … … … [2]

4 marks

Mark scheme: Question Answer Marks Guidance Section A 1(a) Fossil fuels could be: 2 Do not allow ‘wood’ • Coal • Natural gas • Oil / oil derived products. [2  1] 1(b) Solar generated electricity can be stored by charging a 2 Maximum 1 mark if ‘storage’ mentioned without ‘battery’. battery during daytime [1] and then the battery discharges Allow reference to newer types of solar panel that can at night, releasing electricity for use. [1] generate in low light.

This question in 0445/41 May/June 2025

1 (a) Name two fossil fuels. 1 … 2 … [2] (b) Explain how solar energy can be used to provide power at night. … … … [2]

4 marks

Mark scheme: Question Answer Marks Guidance Section A 1(a) Fossil fuels could be: 2 Do not allow ‘wood’ • Coal • Natural gas • Oil / oil derived products. [2  1] 1(b) Solar generated electricity can be stored by charging a 2 Maximum 1 mark if ‘storage’ mentioned without ‘battery’. battery during daytime [1] and then the battery discharges Allow reference to newer types of solar panel that can at night, releasing electricity for use. [1] generate in low light.

This question in 0445/43 May/June 2025

3 (a) Give two benefits of using CAD/CAM in batch production manufacturing. 1 … 2 … [2] (b) Name one manufacturing machine that can be controlled by computer. … [1]

3 marks

Mark scheme: 3(a) CAD/CAM will provide the following benefits: 2 Allow any other valid benefits. • Accuracy Allow ‘Fewer mistakes = less waste’ • Speed in batch production Allow ‘increase efficiency’. • 24/7 working • Reduction in errors • Reduction in labour force • Repeatability [2  1] 3(b) CAM examples could be: 1 Allow any other valid examples. • Lathe, milling machine, router. • Laser cutter Do not allow ‘CNC’ without machine name • 3D printer • Drill • Sewing machine • Router. • Robotic arm

This question in 0445/41 Oct/Nov 2025

3 (a) Give two benefits of using CAD/CAM in batch production manufacturing. 1 … 2 … [2] (b) Name one manufacturing machine that can be controlled by computer. … [1]

3 marks

Mark scheme: 3(a) CAD/CAM will provide the following benefits: 2 Allow any other valid benefits. • Accuracy Allow ‘Fewer mistakes = less waste’ • Speed in batch production Allow ‘increase efficiency’. • 24/7 working • Reduction in errors • Reduction in labour force • Repeatability [2  1] 3(b) CAM examples could be: 1 Allow any other valid examples. • Lathe, milling machine, router. • Laser cutter Do not allow ‘CNC’ without machine name • 3D printer • Drill • Sewing machine • Router. • Robotic arm

This question in 0445/42 Oct/Nov 2025

3 (a) Give two benefits of using CAD/CAM in batch production manufacturing. 1 … 2 … [2] (b) Name one manufacturing machine that can be controlled by computer. … [1]

3 marks

Mark scheme: 3(a) CAD/CAM will provide the following benefits: 2 Allow any other valid benefits. • Accuracy Allow ‘Fewer mistakes = less waste’ • Speed in batch production Allow ‘increase efficiency’. • 24/7 working • Reduction in errors • Reduction in labour force • Repeatability [2  1] 3(b) CAM examples could be: 1 Allow any other valid examples. • Lathe, milling machine, router. • Laser cutter Do not allow ‘CNC’ without machine name • 3D printer • Drill • Sewing machine • Router. • Robotic arm

This question in 0445/43 Oct/Nov 2025