1. Simple
Machines

2. A device that changes the direction of the
Definition:
A device that changes the direction of the
Force that is applied to do a job.
For Example:
In order to lift a crate straight up, you would use a ramp – right?
The ramp changes the vertical lift to a diagonal
You want to lift a vertical height
Ramp

3. It takes less force to push an object at an
angle to gravity than it is to pick it up in line with gravity.
But, since it is a longer distance, you are doing more work with
less effort.
So, it doesn't seem as hard of work using the ramp
Ramp Distance
20N
Vertical Distance
40N
Ramp

4. Simple machines are
Separated into two Families:
1. Lever Family
2. Incline plane Family
Lets start with the levers . . .

5. The
Lever Family

6. - Also called the effort arm
Terminology first -
- Fulcrum – The point at which the
lever pivots.
- Input force – The force that is
applied by you. Your hand.
By pushing or pulling.
- Also called the effort arm
- Output force – The force that is
applied to the object
- Also called the resitance arm

7. 1st Class Lever - - The fulcrum is between the two ends
- The input and output are at the ends
input
output Or
Vis versa
Fulcrum

8. Example?
Crow bar
output
input
Fulcrum

9. 2nd Class Lever - - The fulcrum is is at one end
- The input is at the opposite end of fulcrum
- The output is between input and fulcrum
output
input
Fulcrum

10. Wheel Barrow Example? input output Fulcrum
Don’t forget the other example- you have to draw it.

11. 3rd Class Lever - - The fulcrum is is at one end again
- The output is at the opposite end of fulcrum
- The input is between input and fulcrum
input
output
Fulcrum

12. Example?
Catapult
input
output
Fulcrum

13. Wheel and Axle- Rotation A lever that rotates in a circle around a
center point or fulcrum
Rotation
Center
Point
There is the obvious wheel that is a wheel
and axle but there are some that are not so
obvious.

14. OR like those  Like this -- OR like this -- There does not have to be
Rotation
OR like those 
OR like this --
Rotation
Central
Axis
There does not have to be
an actual wheel. It just has
to spin around a central point.
Central
Axis

15. Pulley -
- Is a wheel and axle with a string, rope, chain, or belt the is pulled around the wheel part.

16. The
Incline plane
Family

17. Simple Inclined
Plane -
- Which is ?
- A Ramp

18. Wedge- When you butt one ramp, Against another
They are always used for cutting or splitting of some kind
It is a wedge.
Examples –
Scissors, Knives, Shears,
Shovels, Spatulas, nails ect . .

19. Screw-
A ramp that is wrapped around a central axis

20. Used for
Fasteners
Augers
Clamps

21. Mechanical Advantage
The numerical value of how much your force is multiplied using a machine.
Formulas-
Input distance
Output Distance
Output Force
Input Force
MA=
MA= OR

22. Example -
If you had a 1st class lever that you wanted to lift a rock with and the input distance was 4 feet and the output distance was only 1 foot, What is the mechanical Advantage?
Output distance
= 1 ft
Input distance
= 4 ft
Fulcrum

23. Input distance Output Distance MA= MA= = 4 4 feet 1 foot
That means that your force that that is pushing up is 4 times as much on the rock you
are lifting. If you push with
10 lbs, you can lift 40lbs.
Output distance
= 1 ft
Input distance
= 4 ft
Fulcrum