DIRECTIONS

1. Use this information to fill in the blanks on your pulley notes.

• Back to How do Machines Work?

• Pulley - a wheel with a rope wrapped around it.

  I. Three types of pulleys
  A. Simple (Fixed) Pulley
  B. Movable Pulley
  C. Compound Pulley (block and tackle)

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  II. Simple (Fixed) Pulley
  A. Gains nothing in force, distance or speed, but
  changes the direction of the input force
  B. Works like a first class lever

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III. Moveable Pulley
A. Moves along a rope or wire
B. Provides a gain in force, but a loss in distance
C. Works like a second class lever
D. The effort applied needs to be only 1/2 the load
E. Example - Pulley used to open & close curtain

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IV. Compound Pulley (block & tackle)
A. Combination of fixed and moveable pulleys
B. Effort equals load divided by the number of weight bearing ropes in the block and tackle.
C. As more parts are added, friction increases
D. Example - Window washer scaffolds and engine hoists