Cambridge IGCSE Design and Technology 0445 — 2005 May/June Paper 4 · Variant 1

Total This document consists of 18 printed pages and 2 blank pages. SP (SJF3472/CG) S78384/2 © UCLES 2005 [Turn over UNIVERSITY OF CAMBRIDGE INTERNATIONAL EXAMINATIONS International General Certificate of Secondary Education DESIGN AND TECHNOLOGY 0445/04 Paper 4 Technology May/June 2005 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 45 minutes. 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 in the spaces provided on the Question Paper. You may use a soft pencil for any diagrams, graphs or rough working. Do not use staples, paper clips, highlighters, glue or correction fluid. Answer any two questions. The number of marks is given in brackets [ ] at the end of each question or part question. You may use a calculator. Centre Number Candidate Number Name For Examiner’s Use If you have been given a label, look at the details. If any details are incorrect or missing, please fill in your correct details in the space given at the top of this page. Stick your personal label here, if provided. 3 2 1 4 www.XtremePapers.com

2 0445/04/M/J/05 1 Fig. 1 shows a tractor, its trailer and detail of the coupling used to connect the tractor and trailer. Fig. 1 (a) (i) Name the type of force that the pin is experiencing when under load. … [1] (ii) Describe the way in which the pin would fail if it were overloaded. … … … [2] (iii) The pin is to be made from mild steel. Give one benefit of using mild steel for the pin. … … [1] (iv) Give one drawback of using mild steel for the pin. … … [1] For Examiner’s Use © UCLES 2005 pin load tailgate

3 0445/04/M/J/05 [Turn over (b) (i) When the tractor is moving, its drive shaft is said to be in torsion. Describe, using sketches and notes, what is meant by the term torsion. [3] (ii) Give any other example of torsion. … [1] (iii) Name two other examples of forces. 1. … [1] 2. … [1] (c) When building the trailer the designer needed to think about different ways of joining the metal frame of the structure. Complete the table below. [6] For Examiner’s Use © UCLES 2005 Name of joining method Diagram Reason for use Gusset plate and bolts Welding Nuts and Bolts

4 0445/04/M/J/05 (d) Fig. 2 represents a corner of the trailer frame. Use graphical means to determine the forces acting in the frame and show the nature of the forces in each member. Fig. 2 [6] For Examiner’s Use © UCLES 2005 30° 200 N C A B

5 0445/04/M/J/05 [Turn over (e) (i) Fig. 3 shows a section of the frame material. Fig. 3 Explain why this section shape is suitable for making the trailer frame. … … … [2] (ii) Fig. 4 shows the tailgate of the trailer. Fig. 4 Explain why it is necessary to add parts A and B to the tailgate. … … … [2] For Examiner’s Use © UCLES 2005 B A

6 0445/04/M/J/05 For Examiner’s Use © UCLES 2005 (f) Fig. 5 shows a concrete beam. Fig. 5 Explain why the beam is constructed in this way. … … … … … … [3] [Total: 30 marks] load

7 0445/04/M/J/05 [Turn over 2 A strain gauge is used to measure strain in the trailer coupling in Fig. 1. (a) (i) Explain, using sketches and notes, the principle behind the operation of a strain gauge. [3] (ii) As part of the testing set up a 741 operational amplifier is used. Complete and label Fig. 6, which shows a simple inverting amplifier circuit. [4] Fig. 6 (iii) Explain the need for a feedback resistor in an inverting amplifier circuit. … … … [2] For Examiner’s Use © UCLES 2005 0 V output voltage V out 741 2 3 6 feedback resistor R f

8 0445/04/M/J/05 For Examiner’s Use © UCLES 2005 (iv) Explain why it is better to buy a 741 Op Amp Integrated Circuit rather than to build the amplifier from separate components. … … … [2] (b) A strain gauge is a type of transducer. Name the transducer used to sense a change in temperature levels. … [1] (c) A Light Dependent Resistor is used to sense a change in light levels. Fig. 7 shows a circuit plan for a light-sensing circuit. Fig. 7 (i) Explain, using sketches and notes, how a reed switch works. [3] (ii) Explain why there are two transistors in this circuit. … … … [2] 0 V +9 V 16 V 16 V motor reed switch and coil 100 kΩ 2.2 kΩ 1 kΩ 680 Ω BFY51 or 2N3053 BC108 1N4001 ORP12 M

9 0445/04/M/J/05 [Turn over (iii) Explain the purpose of the 100 kΩvariable resistor. … … … [2] (iv) The circuit could be modified by using a reed relay. Draw and label a diagram of a D.I.L. Reed Relay. [3] (v) Use notes and sketches to show how a reed switch can be used as a proximity switch in a burglar alarm system. [3] For Examiner’s Use © UCLES 2005

10 0445/04/M/J/05 (d) Fig. 8 shows a circuit to produce a time delay. Fig. 8 (i) This circuit produces a range of time delays between 0 and 30 seconds. Explain how this is possible. … … … [2] (ii) Draw a graph to show the charging of a capacitor. [2] (iii) State the precaution that must be taken when connecting an electrolytic capacitor. … … [1] [Total: 30 marks] For Examiner’s Use © UCLES 2005 0 V +9 V 1 MΩ OFF 100 µF + – ON 2.2 kΩ BFY51 or 2N3053 6 V 0.06 A voltage time

11 0445/04/M/J/05 [Turn over 3 During the designing of the trailer the designer uses models to help in the development of the trailer. (a) (i) Name two ways of modelling the structure of the trailer. 1. … 2. … [2] (ii) The structure is tested to measure its deflection under various loads. Name an accurate method for measuring deflection. … [1] (iii) Members of the structure under load are said to experience moments. Explain the term moments. … … … [2] (iv) Fig. 9 shows the loading of one member of the model. Fig. 9 Calculate the values of the reactions at R and L. [4] For Examiner’s Use © UCLES 2005 40 10 N 100 L R

12 0445/04/M/J/05 (b) (i) Name the main problem with the energy efficiency of the wheels and axle. … [1] (ii) It is decided to use bearings to improve efficiency. Add labels to Fig. 10 to show the following parts: outer race; cage; inner race; ball. Fig. 10 (iii) Name another type of bearing. … [1] (iv) Give an application for the bearing you have mentioned in (b)(iii). … [1] (c) A battery-powered audio alarm is to be fitted to the trailer to warn people when the trailer is reversing. (i) Explain what is meant by the term battery as a power source. … … … [2] (ii) Give one benefit of using a battery as a power source. … … [1] For Examiner’s Use © UCLES 2005 [4]

13 0445/04/M/J/05 [Turn over (iii) Draw and label the circuit symbol for a battery. [2] (iv) Explain how a battery differs from a cell. … … … [2] (d) When designing the alarm circuit a switch is needed that will be activated when the gear selector is moved to the reverse position. (i) Name a suitable switch for this application. … [1] (ii) A toggle switch is selected to turn the alarm unit power on and off. Draw the circuit symbol for this switch in its off position. [2] For Examiner’s Use © UCLES 2005

14 0445/04/M/J/05 (iii) Use notes and sketches to show how the switch would be fixed to a 3 mm acrylic control panel. State precautions needed to avoid cracking the acrylic control panel during fixing. [4] [Total: 30 marks] For Examiner’s Use © UCLES 2005

15 0445/04/M/J/05 [Turn over 4 Fig. 11 shows a mechanism that is used to open a skylight for ventilation. Fig. 11 (a) (i) Name the mechanism. … [1] (ii) Describe the motion conversion that takes place when the mechanism is in operation. … … … [2] (iii) Give one drawback to using this type of mechanism. … … … [2] (iv) Use sketches and notes to show one way that the mechanism could be modified to make it more effective. [4] For Examiner’s Use © UCLES 2005

16 0445/04/M/J/05 (b) (i) The mild steel mechanism is to be lubricated. Explain why this is necessary. … … … [2] (ii) Suggest a suitable lubricant for this use. … [1] (iii) Give one reason for your choice of lubricant in part (b)(ii). … … … [2] (c) Fig. 12 shows a linkage used to open and close shutter (louvre) windows. Fig. 12 (i) Add labels to Fig. 12 to show: load; fixed pivot; moving pivot. [4] (ii) The plate of the mechanism is to be made from brass. Explain why brass is selected. … … … [2] For Examiner’s Use © UCLES 2005 plate rod effort

17 0445/04/M/J/05 [Turn over (iii) The rod is subjected to bending forces. Complete the diagram below to show compression, tension and the neutral axis. [3] (d) Fig. 13 shows a wheel and axle mechanism. Fig. 13 (i) If the radius of the wheel is 200 and the radius of the axle is 50 calculate the Mechanical Advantage of the wheel and axle. [3] (ii) Explain how the wheel and axle makes it easier for the user to lift heavy loads. … … … [2] For Examiner’s Use © UCLES 2005 axle wheel effort load

18 0445/04/M/J/05 (iii) Calculate the effort required to lift a load of 300 N. Assume that the wheel and axle are 100% efficient. [2] [Total: 30 marks] For Examiner’s Use © UCLES 2005

20 0445/04/M/J/05 BLANK PAGE Every reasonable effort has been made to trace all copyright holders where the publishers (i.e. UCLES) are aware that third-party material has been reproduced. The publishers would be pleased to hear from anyone whose rights they have unwittingly infringed. University of Cambridge International Examinations is part of the University of Cambridge Local Examinations Syndicate (UCLES), which is itself a department of the University of Cambridge.