Constructed by Thomasboro 7th graders

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PULLEYS

• Constructed by Thomasboro 7th graders

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Fixed pulleys

• Change the direction of the applied force (you
  can pull down to move an object up)
• Do not change the force applied to the object
  (resistance)
• Fixed pulleys do not move.

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Pictures of fixed pulleys
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Videos of fixed pulleys
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Multiple Fixed Pulleys
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Movable pulleys

• Movable pulleys move they are not fixed.
• Increase the force applied to resistance
• Do NOT change the direction of the force (you
  must pull in the direction you want to move the
  object)

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Movable pulley in action

• What would you measure to determine the
  resistance distance?
• Resistance force?

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Block and Tackles

• Contain both fixed and movable pulleys and have
  the advantages of both
• Change the direction of the force
• Increase the force applied to resistance

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Block Tackle in Action
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Review

• Which two pulleys allow you to pull down to move
  an object up?
• Which two pulleys allow you to use less force to
  lift something heavy?
• Which one of the three types of pulleys would be
  most useful to lift a car to a height above your
  head?