1. Simple Machines

2. Six Types of Machines -- Inclined plane -- Wedge -- Lever
-- Wheel and Axle
-- Screw
-- Pulley
A simple machine does work by
changing the amount or
direction of the force needed
to apply.
It can also increase the distance
of the output force.

3. Inclined Plane Friction decreases Flat, slanted efficiency surface
Force is
exerted over
a longer
distance
Input force is
less than
output force
Friction
decreases
efficiency
The longer the
inclined plane,
the less input force is
needed to make a push or pull

4. Wedge Like two inclined planes together that can move The longer
Device that
is thick at one
end & tapers to
a thin edge
at the other
The longer
and thinner a
wedge, the less
input force
needed
Like two
inclined planes
together that
can move
wedge insert
itself into
Input force
something
makes the

5. Lever Fixed point in lever is 3 Advant-ages called fulcrum FULCRUM
around a
that pivots
Rigid bar
Fixed point
in lever is
called
fulcrum 3
Advant-ages
In center of
Fulcrums do
have to be
lever
NOT
Changes
direction,
decreases force OR
increases
distance

6. First Class Lever

7. Second Class Lever

8. Third Class Lever

9. Screws Inclined plane wrapped around a cylinder
Spiral inclined plane forms the threads of the screw
Closer the threads are, the greater the mechanical advantage
Increased distance results in increased output force

10. Checkpoints How are wedges and screws related?
Why does a lid that requires eight twists to seal a jar require less input force than a similar lid that requires four twists?

11. Wheel and Axle
Two circular or cylindrical objects that are fastened together and that rotate about a common axis
In a screwdriver handle is the wheel and the shaft is the axle
Doorknob – knob is the wheels and shaft is the axle
The larger the circumference of the wheel, the less input force you have to do

12. Pulley Grooved wheels with a rope wrapped around it
When you pull on the rope, you use the pulley
Fixed pulley – attached to a structure; used to raise a sail
(changes direction only)
Movable pulley – attach a pulley to the object you want to move (changes direction & decreases force)
Pulley systems – Combination of fixed and movable pulley systems (changes direction & decreases force)

13. Complex Machines Machine that utilizes two or more simple machines
Your Rube Goldberg inventions will be a complex machine made of 4 or more simple machines
Pencil sharpener