Key term
CCEA A-Level Technology and Design 8900
Material Selection and Wood
Metals
Plastics
Composite and Emerging Materials
Processing Materials
Product Analysis and Design Communication
Design for Manufacture, Quality and Safety
Electronic Control SystemsOption A
Topic overviewControl systems, feedback and electronics safetyResistors, Ohm's law and power ratingsCapacitors and RC timingPotential dividers, sensors and comparatorsSwitches, pull-up and pull-down resistorsOutput devices and LEDsTransistors, Darlington pairs and thyristorsLogic gates, truth tables and flip-flops555 monostable and astable timers
Microelectronic Control SystemsOption A
Topic overviewMicrocontroller systems, ADCs and DACsStrain gauges and bridge circuitsOptical switches, encoded discs and Schmitt triggersOp-amp amplifiers and gainZener diodes and voltage regulatorsKarnaugh maps and binary countersSeven-segment, LCD and dot matrix displaysPIC flowcharts and programmingDC motors, stepper motors and driver circuits
Mechanical and Pneumatic ComponentsOption B
Topic overviewOpen and closed loop mechanical and pneumatic controlSafe working with compressed air and mechanismsLevers, linkages and momentsGear types and gear trainsPulleys, belts, chains and shaft fixingsCams, cranks and converting motionCompressed air supply and pneumatic valvesCylinders, shuttle valves, restrictors and reservoirsPneumatic circuits for logic, timing and speed control
Mechanical and Pneumatic SystemsOption B
Topic overviewHydraulics, system limitations and plant safetyTorque, work, power and air consumptionVacuum handling, proximity sensors and 5/3 valvesSequential and cascade pneumatic circuitsCam profiles and follower displacement diagramsGear geometry, pulley blocks and ratchetsToggles, treadles, shafts and couplingsFriction, brakes and clutchesBearings, lubrication and seals
Designing and Manufacturing ProductsOption C
Topic overviewResearch, questionnaires and specificationsIdea generation, critiques and computer simulationManufacturing planning and product evaluationCFRP, GRP, Kevlar and tungsten carbideSmart materials, nanotechnology and biophotovoltaicsIsometric, perspective and assembly drawingLaminating, steam bending, cutting and printing processesRisk assessment and product safety lawScales of production, JIT and cell productionQuality assurance, ISO 9001 and continuous improvementDesign influences and intellectual property rights
Product Design in Industry and SocietyOption C
Topic overviewLife-cycle environmental impact and climate changeThe 6Rs, waste and environmental legislationSustainable metals, plastics and degradable polymersProduct life cycles, consumer types and relaunchesCAD, CAM, 3D scanning and quick-change mouldingMarket pull, technology push and market strategyPrice, place and promotionJigs, fixtures and ICT in quality controlDesign for maintenance, inclusion and scale productionRendering, typography and presentationDyson, Baylis, Memphis and Apple
Product Development
Product and System Design and Manufacture
Mechanical and Pneumatic Systems
Torque, work, power and air consumption
- 3 things to know
- A2 1
Overview
Torque, work and power with worked calculations, the effect of gearing on torque, potential and kinetic energy, and cylinder air consumption and free air conversion.
What you need to know
Answer each one before you reveal it.
Your recallNot started
Numbers
A force of 50 N is applied to a spanner 0.25 m from the centre of the nut. Calculate the torque.
Key term
How does a speed-reducing gear train affect torque?
Questions from this subtopic
Each one with the model answer underneath.
- 1
Define torque and give its unit.
Model answer
Torque is the turning moment a force produces about the axis of a shaft. Torque = force × radius, measured in N m.
- 2
A force of 50 N is applied to a spanner 0.25 m from the centre of the nut. Calculate the torque.
Model answer
The torque on the nut is 12.5 N m. Torque = 50 × 0.25 = 12.5 N m.
- 3
How does a speed-reducing gear train affect torque?
Model answer
Output torque rises in proportion to the velocity ratio, less the losses. Output torque = input torque × VR × efficiency.
- 4
A motor delivers 0.5 N m to a gearbox with a velocity ratio of 20:1 and an efficiency of 80%. Calculate the output torque.
Model answer
The output torque is 8 N m. Output torque = 0.5 × 20 × 0.8 = 8 N m.
- 5
Define work done and give its unit.
Model answer
Work done is the force multiplied by the distance moved in the direction of the force. Work is measured in joules, where 1 J = 1 N m.
- 6
A pusher cylinder applies 500 N over a stroke of 0.4 m in 0.5 s. Calculate the work done and the power.
Model answer
The work done is 200 J and the power is 400 W. Work = 500 × 0.4 = 200 J, and power = 200 ÷ 0.5 = 400 W.
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