Cambridge IGCSE Design and Technology 0445 — 2010 May/June Paper 4 · Variant 2

[Turn over *6746806804* READ THESE INSTRUCTIONS FIRST Write your Centre number, candidate number and name on all the work you hand in. Write in dark blue or black pen. You may use a soft pencil for any diagrams or graphs. Do not use staples, paper clips, highlighters, glue or correction fl uid. DO NOT WRITE IN ANY BARCODES. You may use a calculator. Section A Answer all questions. Section B Answer one question. At the end of the examination, fasten all your work securely together. The number of marks is given in brackets [ ] at the end of each question or part question. For Examiner’s Use Section A Section B Total DESIGN AND TECHNOLOGY 0445/42 Paper 4 Systems and Control May/June 2010 1 hour Candidates answer on the Question Paper. No Additional Materials are required. To be taken together with Paper 1 in one session of 2 hours and 15 minutes. UNIVERSITY OF CAMBRIDGE INTERNATIONAL EXAMINATIONS International General Certifi cate of Secondary Education This document consists of an 15 printed pages and 1 blank page. [Turn over IB10 06_0445_42/2RP © UCLES 2010 www.XtremePapers.com

2 0445/42/M/J/10 © UCLES 2010 For Examiner’s Use Section A Answer all questions in this section. 1 Fig. 1 shows a black box diagram of a gearbox. ‘black box’ gearbox input output Fig. 1 Name the two types of motion indicated on Fig. 1. … [1] … [1] 2 Fig. 2 shows a diagram of a cam. A Fig. 2 (a) Name the type of cam shown in Fig. 2. … [1] (b) Name the part labelled A in Fig. 2. … [1]

3 0445/42/M/J/10 © UCLES 2010 [Turn over For Examiner’s Use 3 Complete the table below giving one example of the use of each gear. Method Example of use Spur gear Bevel gear Rack and pinion [3] 4 Mechanical systems often require lubrication. State one reason for needing lubrication in mechanical systems. … [1] 5 Fig. 3 shows a variety of structures. Fig. 3 girder (a) (i) Name one frame structure. … [1] (ii) Name one shell structure. … [1] (b) (i) Identify the type of force acting in the cables supporting the girder. … [1] (ii) Structures are subjected to moments (turning forces). Defi ne the term ‘moment’. … … [2]

4 0445/42/M/J/10 © UCLES 2010 For Examiner’s Use 6 Explain the need for triangulation in structures. … … [2] 7 Name one way of accurately measuring defl ection in structures. … [1] 8 When fault fi nding in electronic circuits a variety of meters is used. Complete the table below. Meter Units measured Example of use Ammeter Measure current fl owing through a transistor Volts Measure voltage across a potential divider Check the continuity of an electrical lead [4] 9 Fig. 4 shows a simple alarm circuit. 2 K 100 K +9 V Fig. 4 B A (a) Name the component labelled A. … [1]

5 0445/42/M/J/10 © UCLES 2010 [Turn over For Examiner’s Use (b) Explain the purpose of component B in this circuit. … … [2] 10 Logic gates are used to control many electronic devices. Sketch the symbol for an AND gate. [2]

6 0445/42/M/J/10 © UCLES 2010 For Examiner’s Use Section B Answer one question from this section. 11 (a) Complete Fig. 5 which shows a selection of switches. Type Appearance Application [1] Non-contact operation by magnet for detecting the opening or closing of doors/windows Tilt [2] Membrane panel [3] Waterproof keypads Fig. 5 (b) A slide switch can be used to select different functions in a circuit. Draw and label a simple circuit diagram to show this operation. [3]

7 0445/42/M/J/10 © UCLES 2010 [Turn over For Examiner’s Use (c) A transistor is used as a switch to control the fl ow of current in circuits. (i) Explain how a transistor works as a switch. … … … [3] (ii) Draw and label an npn transistor to show the: ● base; ● collector; ● emitter. [4] (d) Describe how you would solder a transistor into a circuit without damaging it. … … [2] (e) Logic gates are a form of switch. They are used to control electronic devices. Give one example of the use of logic gates to control an electronic device. … [1]

8 0445/42/M/J/10 © UCLES 2010 For Examiner’s Use (f) Fig. 6 shows a diagram of a circuit used to model a logic gate. Push Push A B Q Fig. 6 9 V 0 V (i) Name the type of gate that this circuit is modelling. … [1] (ii) Complete the truth table for this gate. A B Q 0 0 0 1 1 0 1 1 1 [3] (iii) Sketch the logic symbol for the gate shown. [2]

9 0445/42/M/J/10 © UCLES 2010 [Turn over For Examiner’s Use 12 Fig. 7 shows a variety of pulley systems. A B C input input output Fig. 7 (a) Complete the table below to describe the motion transmission for each pulley system shown in Fig. 7. Pulley system Input Output direction Output speed A Clockwise Increased B Clockwise C Clockwise [5] (b) Fig. 8 shows a pulley system. Calculate the driven pulley speed. driven pulley Ø30 driver pulley Ø90 1000 rpm Fig. 8 [3]

10 0445/42/M/J/10 © UCLES 2010 For Examiner’s Use (c) Fig. 9 shows a variety of pulley belts. P Q R S Fig. 9 (i) Belts P, Q and R are used in small pulley systems. Give one example of a system using one of these types of belt. … [1] (ii) Explain why belt S would be used in larger machinery pulley systems. … … [2] (iii) Give one example of a machine that uses belt S. … [1] (d) Fig. 10 shows a simple gear system. 12 teeth 24 teeth driver Fig. 10 (i) Calculate the Velocity Ratio for this system. [3]

11 0445/42/M/J/10 © UCLES 2010 [Turn over For Examiner’s Use (ii) State the effect that the gear system shown in Fig. 10 has on output speed. … … [1] (iii) The driven gear will turn in the opposite direction to the driver gear. Explain, using notes and sketches, how the driven gear can be made to turn in the same direction as the driver gear. [3] (e) Some mechanical systems use a ratchet and pawl mechanism. (i) Give one example of the use of a ratchet and pawl. … [1] (ii) Explain the purpose of a ratchet and pawl mechanism. … … [2] (iii) Sketch and label a ratchet and pawl mechanism. [3]

12 0445/42/M/J/10 © UCLES 2010 For Examiner’s Use 13 Fig. 11 shows a towel rail fi xed to a wall. towel rail wall Fig. 11 (a) Name the type of structure shown. … [1] (b) Redraw the towel rail and clearly label the: ● tension forces; ● compression forces; ● load. [3] (c) The towel rail is said to be in equilibrium. Use notes and sketches to explain the term ‘equilibrium’. [3]

13 0445/42/M/J/10 © UCLES 2010 [Turn over For Examiner’s Use (d) The weight of the towel is 12 N acting 600 mm from the wall. Calculate the reaction at the wall. [3] (e) The towel rail is made from stainless steel tubing. Explain in structural terms why tubing is the best choice for the towel rail. … … … [2] (f) Fig. 12 shows the wall mount for the towel rail. fixing holes Fig. 12 (i) Explain why there are three fi xing holes on the mount. … … [2] (ii) Name the type of force applied by a screwdriver when fi xing the mount to a wall. … [1] (iii) Explain what could happen to the screw if too much force is applied. … … … [2]

14 0445/42/M/J/10 © UCLES 2010 For Examiner’s Use (g) Fig. 13 shows a metal stepladder. tread rail legs Fig. 13 (i) Explain why the legs of the stepladder form a triangular shape when opened. … … … [2] (ii) Explain the purpose of the rail. … … … [2] (iii) Explain why the tread has folded edges. … … … [2]

15 0445/42/M/J/10 © UCLES 2010 For Examiner’s Use (iv) Use notes and sketches to show the effect of loading on one of the stepladder treads. [2]

16 0445/42/M/J/10 Permission to reproduce items where third-party owned material protected by copyright is included has been sought and cleared where possible. Every reasonable effort has been made by the publisher (UCLES) to trace copyright holders, but if any items requiring clearance have unwittingly been included the publisher will be pleased to make amends at the earliest possible opportunity. University of Cambridge International Examinations is part of the Cambridge Assessment Group. Cambridge Assessment is the brand name of University of Cambridge Local Examinations Syndicate (UCLES), which is itself a department of the University of Cambridge. BLANK PAGE © UCLES 2010

UNIVERSITY OF CAMBRIDGE INTERNATIONAL EXAMINATIONS International General Certificate of Secondary Education MARK SCHEME for the May/June 2010 question paper for the guidance of teachers 0445 DESIGN AND TECHNOLOGY 0445/42 Paper 42 (Systems and Control), maximum raw mark 50 This mark scheme is published as an aid to teachers and candidates, to indicate the requirements of the examination. It shows the basis on which Examiners were instructed to award marks. It does not indicate the details of the discussions that took place at an Examiners’ meeting before marking began, which would have considered the acceptability of alternative answers. Mark schemes must be read in conjunction with the question papers and the report on the examination. • CIE will not enter into discussions or correspondence in connection with these mark schemes. CIE is publishing the mark schemes for the May/June 2010 question papers for most IGCSE, GCE Advanced Level and Advanced Subsidiary Level syllabuses and some Ordinary Level syllabuses. www.XtremePapers.com

Page 2 Mark Scheme: Teachers’ version Syllabus Paper IGCSE – May/June 2010 0445 42 © UCLES 2010 Section A 1 Input: Rotary (CW) [1] Output: Reciprocating [1] 2 (a) Eccentric [1] (b) Follower [1] 3 Method Example of use Spur gears Lathe gear box (1) Bevel gears Hand drill (1) Rack and pinion Car steering system (1) [3] 4 Reduce friction/wear and tear/smooth running [1] 5 (a) (i) Crane tower/building framework/pylons [1] (ii) Tanker/boat hull/car body [1] (b) (i) Tension [1] (ii) Force x perpendicular distance from pivot [2] 6 Increases rigidity (1) and ability to withstand buckling (1) [2] Distribution of loading (1) 7 Strain gauge/Dial gauge [1] 8 Meter Units measured Example of use Ammeter AMPS (1) Measure current flowing through a transistor. Voltmeter Volts Measure voltage across a potential divider. (1) Multi-meter (1) OHMS (1) Check the continuity of an electrical lead. [4]

Page 3 Mark Scheme: Teachers’ version Syllabus Paper IGCSE – May/June 2010 0445 42 © UCLES 2010 9 (a) LDR (Light dependant resistor) [1] (b) Protects (1) the Transistor from back EMF (1) created by the coil of the relay. [2] 10 [2] [Total: 25] Section B 11 (a) (i) Reed switch [1] (ii) A burglar alarm (1) on a bicycle that is activated when the bike is moved (1). [2] (iii) [3] (b) [3] Appropriate example (1) Circuit works (1) Correctly drawn to convention (1) keypad (1) spacer (1) connections (1)

Page 4 Mark Scheme: Teachers’ version Syllabus Paper IGCSE – May/June 2010 0445 42 © UCLES 2010 (c) (i) A small current flowing at the base (1) enables a large current (1) to flow through collector/emitter circuit (1). [3] (ii) [4] (d) Clamp a heat sink (1) to leg that is being soldered (1) [2] (e) Burglar alarm system/washing machine controller [1] (f) (i) OR [1] (ii) A B Q 0 0 (1) 0 0 1 1 (1) 1 0 1 1 1 (1) 1 [3] (iii) [2] c (1), e (1), b (1) Drawing (1) (1) (1)

Page 5 Mark Scheme: Teachers’ version Syllabus Paper IGCSE – May/June 2010 0445 42 © UCLES 2010 12 (a) Pulley System Input Output Direction Output Speed A Clockwise Anticlockwise (1) Increased B Clockwise Clockwise (1) Increased C Anticlockwise (1) Clockwise Decreased (1) [4] (b) speed of driven = speed driver × Ø of driver (1) Ø of driven speed of driven = 1000 rpm × 90 mm (1) 30 mm speed of driven = 3000 rpm (1) [3] (c) (i) Record player turntable/vacuum cleaner/sewing machine [1] (ii) Wedge into their pulley wheels (1) to avoid slipping (1) [2] (iii) Pillar drill/lathe/car engine fan belt [1] (d) (i) Velocity Ratio = Teeth on driver gear Teeth on the driven gear (1) VR = 12 / 24 (1) VR = 1 : 2 (1) [3] (ii) Decreased [1] (iii) [3] Accept schematic version Idler gear (1) Two spur gears (1) Motion shown (1)

Page 6 Mark Scheme: Teachers’ version Syllabus Paper IGCSE – May/June 2010 0445 42 © UCLES 2010 (e) (i) Winch/fishing reel [1] (ii) Makes a shaft can rotate (1) in one direction only (1). [2] (iii) [3] [Total: 25] 13 (a) Cantilever [1] (b) [3] (c) weight W × distance Z = weight V × distance Y (1) [3] (1) (1) (1) (1) (1) (1) (1) (1)

Page 7 Mark Scheme: Teachers’ version Syllabus Paper IGCSE – May/June 2010 0445 42 © UCLES 2010 (d) Reaction at the wall = Force × distance from the wall (1) Reaction at the wall = 12 N × 600 mm (1) Reaction at the wall = 7.2 Nm (1) [3] (e) Tubing has a good strength to weight ratio (1). It will support a load without placing too much load on the wall due to its own weight (1). [2] (f) (i) To distribute the load across a larger area (1) thus minimising the risk of a single fixing failure (1). [2] (ii) Torsion [1] (iii) The screw could shear (1) through its shaft (1)/or the screwhead could break off (1). [2] (g) (i) Increased rigidity of the frame (1) and thus more stability (1). [2] (ii) Prevents the legs of the steps from splaying (1) thus making the steps safer and more robust (1). [2] (iii) Increases the rigidity (1) and the capability to bear bending loads (1). [2] (iv) Use notes and sketches to show the effect of loading on one of the stepladder treads. [2] [Total: 25]