Machines video lecture

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Machines video lecture

Created 3 years ago

Duration 0:30:19
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Slide Content
  1. Machines

    Slide 1 - Machines

    • Mechanical Advantage &
    • Efficiency
  2. Simple Machines

    Slide 2 - Simple Machines

    • Lever
    • Inclined Plane
    • Pulley
    • Wheel & axle
    • Wedge
    • Screw
  3. Lever

    Slide 3 - Lever

    • F in
    • F out
    • din =distance between applied force and fulcrum
    • dout =distance between load and fulcrum
    • hin = the heigt force end moves
    • hout = the height load end moves
    • hin
    • hout
    • dout
    • din
    • dout
    • din
    • See-saw
    • Scissors
    • pliers
    • Hole puncher
    • Bottle opener
    • wheelbarrow
    • Fishing rod
    • tweezers
    • tongs
  4. Slide 4

    • Inclined Plane:
    • Output Force = Fout
    • Input Force = Fin
    • Work input = Work Output
    • W in = W out
    • F in  d in = F out  d out
    • Input distance= din
    • Output distance = dout
  5. What if there is friction?:

    Slide 5 - What if there is friction?:

    • Work input + Work done by friction = Work Output
    • W in + W f = W out
  6. Mechanical Advantage

    Slide 6 - Mechanical Advantage

    • Ideal Mechanical Advantage (IMA) depends only on the geometry of the system.
    • However situations are never ideal!
    • Actual Mechanical Advantage:
  7. Efficiency:

    Slide 7 - Efficiency:

    • The ratio of the work output to work input.
  8. Ex:

    Slide 8 - Ex:

    • Clyde, a stubborn 350 kg mule refuses to walk into the barn, so farmer McDonald must drag him up a 5 m ramp, which stands 0.5 m above ground level. He pulls with 450 N of force.
    • What is the ideal MA?
    • Find work input, work output and friction.
    • What is the actual MA?
    • Find the Efficiency of the ramp.
  9. Ex:

    Slide 9 - Ex:

    • Clyde, a stubborn 350 kg mule refuses to walk into the barn, so farmer McDonald must drag him up a 5 m ramp, which stands 0.5 m above ground level. He pulls with 450 N of force.
    • What is the ideal MA?
    • Find work input, work output and friction.
    • What is the actual MA?
    • Find the Efficiency of the ramp.
  10. Ex:

    Slide 10 - Ex:

    • Winnie holds a 50 N tray of lemonades in one hand. The length of her arm from her hand to elbow is 30 cm and her biceps exert a force 5 cm from her elbow. How much force must her biceps exert to allow her to hold the tray?
  11. Ex:

    Slide 11 - Ex:

    • Winnie holds a 50 N tray of lemonades in one hand. The length of her arm from her hand to elbow is 30 cm and her biceps exert a force 5 cm from her elbow. How much force must her biceps exert to allow her to hold the tray?
  12. Pulleys: What is the Ideal Mechanical Advantage?

    Slide 12 - Pulleys: What is the Ideal Mechanical Advantage?

  13. Ex:

    Slide 13 - Ex:

    • Using a pulley system, Sam lifts the 1000 N engine 0.5 m, but exerts a force of 60 N on 10 m of rope to do so.
    • What is the theoretical (ideal) mechanical advantage of the pulley system? How many supporting strands does it have?
    • What is the ACTUAL mechanical advantage of the pulley system?
    • How much work is done on the engine? How much work does Sam do?
    • What is the work done by friction?
  14. Ex:

    Slide 14 - Ex:

    • Using a pulley system, Sam lifts the 1000 N engine 0.5 m, but exerts a force of 60 N on 10 m of rope to do so.
    • What is the theoretical (ideal) mechanical advantage of the pulley system? How many supporting strands does it have?
    • What is the ACTUAL mechanical advantage of the pulley system?
    • How much work is done on the engine? How much work does Sam do?
    • What is the work done by friction?