MATERIALS AND THEIR WORKING PROPERTIES

• What are the four types of motion?

  Linear, rotational, oscillatory, and periodic
• If a wheel rotates at 300 rpm, how many revolutions does it make in 10 seconds?

  50 revolutions
• How long does it take a robot traveling at 0.8 m/s to cover 5 m?

  6.25 seconds
• What are the components of a lever diagram that doubles the applied effort force?

  • Effort
  • Load
  • Fulcrum
• What are the mechanisms and their motion conversions to sketch and label?

  1. Crank and slider: Converts rotary to linear motion
  2. Rack and pinion: Converts rotary to linear motion
  3. Bell crank: Converts linear to rotary motion
• What are the similarities and differences between a simple gear train and a belt and pulley drive system?

  Similarities:

  • Both transmit power
  • Both can change speed

  
  

  Differences:

  • Gears mesh, belts do not
  • Gears can slip, belts can stretch
• What is the standard size progression of paper sheets?

  • Each size is half the previous size
  • Example: A3 is twice A4
• What is the weight classification for paper and board?

  Weight greater than 170 gsm is board
• What is the thickness of paper measured in?

  Grams per square metre (gsm)
• What is the thickness of board measured in?

  Microns
• What are common types of paper and their properties?

  1. Layout paper: Smooth, 50 gsm, for sketching
  2. Tracing paper: Transparent, 40 gsm, for copying
  3. Copier paper: 80 gsm, for printing
  4. Cartridge paper: 80-140 gsm, for drawing
• What is virgin fibre paper made from?

  New wood fibres called cellulose
• How is recycled paper produced?

  By soaking waste paper to separate fibres
• What happens to paper fibres each time they are recycled?

  They get shorter and weaker
• What is the composition of recycled paper based on virgin pulp percentage?

  • 85-100% virgin pulp: High-quality paper
  • 70-85% virgin pulp: Household applications
  • 50-70% virgin pulp: Newspaper
• What are the properties and uses of card and cardboard?

  1. Card: 180-300 gsm, for greetings cards
  2. Cardboard: 300 microns+, for packaging
  3. Folding boxboard: Rigid, for frozen foods
  4. Corrugated cardboard: Lightweight, for fragile items
• What are the two types of lamination?

  1. Coating during paper-making
  2. Applying clear plastic film
• What are the properties of non-ferrous metals?

  Do not rust, mostly non-magnetic
• Why is aluminium widely recycled?

  It takes less energy to recycle
• What are alloys?

  Metals combined to improve properties
• What is the definition of a polymer?

  Substance made of smaller molecular units
• What are the characteristics of thermoforming polymers?

  Can be softened and reshaped multiple times
• What are the characteristics of thermosetting polymers?

  Cannot be reheated or reshaped once set
• What is the main use of thermosetting polymers?

  Excellent insulators
• What is the main property of non-ferrous metals?

  Do not contain iron
• What is the significance of aluminium in recycling?

  Requires less energy to recycle than produce
• What is the definition of an alloy?

  Combination of metals to enhance properties
• What is the main characteristic of synthetic polymers?

  Made from crude oil, unsustainable resource
• What is the most common biopolymer?

  Polylactate acid (PLA)
• What are the stock forms of polymers?

  Sheet, film, bar, rod, granules, powder, tube
• What happens to thermoforming polymers when heated?

  They soften and can be reshaped
• What happens to thermosetting polymers when heated?

  They maintain their shape and cannot be reshaped
• What is the main property of non-ferrous metals?

  Do not rust or corrode easily
• What is the significance of aluminium in recycling?

  Requires significantly less energy to recycle
• What are non-ferrous metals?

  Metals that do not contain iron
• Why are non-ferrous metals ideal for electronic devices?

  Most are not magnetic
• What is the second most widely used metal after steel?

  Aluminium
• How much energy does it take to recycle aluminium compared to producing it?

  95% less energy
• What are the properties and uses of aluminium?

  • Properties: Extremely lightweight, soft, malleable
  • Uses: Drinks cans, foils, kitchen utensils, aeroplane parts
• What are the properties and uses of copper?

  • Properties: Good electrical and thermal conductivity, corrosion resistance
  • Uses: Plumbing pipes, electrical wire, roofing