What are the six simple machines?
• The Lever
• The Inclined Plane
• The Wedge
• The Screw
• The Wheel and Axle
• The Pulley
What is Work?
• Work is defined as a force acting on an object to
move it across a distance.
What is Motion?
• Motion is change of location or position of an
object with respect to time.
Work equals force times distance.
Or:
x
W= F D
3 ways that Simple Machines make work easier.
1. By increasing the force that can be applied to an
object.
2. By increasing the distance over which the force
is applied.
3. By changing the direction of a force.
A force is a push or pull
A lever is a stiff bar that rests on a
support called a fulcrum which
lifts or moves loads.
The parts of a lever are:
•
fulcrum (pivot point)
• load (the thing being moved)
• effort (the thing doing the moving)
1st Class Lever = fulcrum is located
between the applied force and the load.
Examples are:
• Can opener and/or bottle opener
• Crowbar
• Hand trucks
• Pliers (double lever)
• Scissors (double lever)
• Seesaw (aka teeter-totter)
A 2nd class lever has the load
between the fulcrum and the effort
force.
Examples are:
• wheel barrow
• hole puncher
• stapler
• nutcracker
A third class lever is one where
force is applied in between the
fulcrum and the load being moved.
Examples are:
• Fishing rod
• Tweezers
• Catapult
• Diving board
An inclined plane is a slanting surface
connecting a lower level to a higher
level. An incline plane requires less
force over a greater distance. The
inclined plane is used to change the
elevation of an object without lifting
the object directly.
Examples of
inclined plane
include wedge
chisels, sloping
roads, ramps,
and plows.
A wedge is an object with at least one slanting
side ending in a sharp edge, which can be used
to cut materials. A wedge is made of two
inclined planes. Examples are push pins, your
own teeth, nails, a sledge hammer, an axe, a
knife, a razor blade, anything that splits, cuts,
or divides another object including air and
water.
A screw is an inclined plane wrapped
around a pole. A screw may be used to
fasten things together, wedge things
apart, cut material, or lift things. Some
examples are key rings, a light bulb, a
jar lid, a door knob, a bolt, an ice auger,
to name a few.
A wheel with a rod, called an axle,
through its center used to lift or
move loads. In the example to the
right effort is applied to the wheel to
lift a load (water).
A pulley is a simple machine that uses grooved
wheels that turn around an axel. A rope is used to
raise, lower or move a load. A pulley changes the
direction of force.
Examples of pulleys include:
•Elevators use multiple pulleys in order to function.
•Many types of exercise equipment use pulleys in order to function.
•Curtains at a theatre are moved using pulley systems that pull the curtains apart.
•Flagpoles use pulleys in order to hoist the flag up or to bring it down.
•Pulleys can be used to place birdfeeders high in trees or on poles.
•Pulleys can be used to extend ladders.
•Sails on sailboats are raised and lowered using pulleys.
•Garage doors raise and lower utilizing a pulley system.
•Rock climbers use pulleys to help them to climb.
Energy is the capacity to do work or to perform vigorous activity.
The law of conservation of energy is a law of science that states that
energy cannot be created or destroyed, but only changed from one
form into another or transferred from one object to another.