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
• 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
• 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
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
Pulley Load (N) Direction Scale Effort (N)
System Of Pull Reading
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.