Pulleys

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					 Pulleys

Investigation 1
 A Different Simple Machine
• If you needed to lift a large bale of
  hay to the top of a huge stack of
  hay what type of machine do you
  think that you could use?
• What would it look like?
• What would its advantage be?
       Single Fixed Pulley
• Single= one
• Fixed= attached & stays in place
• Pulley= Grooved wheel
Investigate:
• Can you set up a single fixed pulley
  system so that it will offer an
  advantage to lift a load? (IE: It
  should be able to lift the bale of hay
  to the top of the stack.)
     Single Movable Pulley
• Single- One grooved wheel
• Moveable- Wheel needs to move
• Pulley- Lifts a load
• A moveable pulley always moves with
  the load.
Investigate:
• Try to create a single moveable pulley.
  It should still lift the load, BUT the
  wheel needs to move.
 Which system gave you a
greater advantage to lift the
           load?
How can we find out for sure?
• Let’s collect data by measuring it.
• Spring scale
  -zero the scale,
  -reading the scale (each bar is worth
  2/10 or 0.2 of a Newton)
  -add 0.5 N only when the effort pulls
  down to account for the scale’s own
  force
                  Collect Data:
Pulley         Load (N)   Direction   Scale     Effort (N)
System                    Of Pull     Reading
                                      (N)
Single-fixed


Single-
moveable
   Reviewing Our Learning
• You can set up a pulley in 2 ways
  1. Fixed Pulley
  2. Moveable Pulley
• Single Fixed Pulleys change the
  direction of the effort only.
• Single moveable pulleys reduce the
  effort needed to lift the load.

				
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