What is a Simple Machine?
• Machines are used to reduce the amount
of force required to do work.
• Ex: lift a load
• But you must apply this force over a
greater distance.
The amount of WORK
stays the same
Inclined Plane
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• A slope or a ramp.
• Any slanted surface used to
raise a load from a lower
level to a higher level.
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Examples:
• ramps for wheel chairs
• a ramp used by a workman to push a heavy
load on wheels up into a truck
• an escalator
• an inclined plane was used to move huge
stones to build the Egyptian Pyramids
• ramps to load luggage
onto a plane
• Advantage: Helps a person
to move or raise heavy
objects.
• Advantage: Lift with LESS
FORCE…
• Disadvantage: but the
distance over which it
moves is greater.
http://www.sciencetech.technomuses.ca/english/schoolzone/Info_Simple_M
achines2.cfm#pulley
Pulleys
A simple machine.
A wheel with a groove in it.
A rope/cable goes into the
groove.
Pulleys Can:
• Change direction of
force
• Change amount
of force
• The amount of
WORK stays the
same
Fixed Pulley
• Stays attached.
• Does NOT change the
amount of force
• Only changes the
direction of force.
• Easier to push down than to
pull up.
• The amount of WORK
stays the same
The amount of
WORK stays the
same
http://www.the-office.com/summerlift/pulleybasics.htm
Moveable Pulley
• The mass is attached to the
pulley.
• The pulley moves
on the rope.
Advantage:
Cuts the amount of force needed
to move the mass.
Disadvantage:
You have to pull or push the
pulley up or down.
• The amount of WORK stays the
same
The amount of
WORK stays the
same
http://www.the-office.com/summerlift/pulleybasics.htm
What happens to the
amount of work?
Which one
changes
the
direction
of the
force?
Which one
reduces
the amount
of force?