1. * Do work with one movement
Simple Machines
* Do work with one movement

2. Six Types:
- Inclined plane - Wedge - Screw - Lever - Wheel and axle - Pulley

3. Inclined Plane
A flat, sloped surface Allows you to exert your input force over a longer distance. Mechanical advantage = length of incline height of incline

5. Wedges
Wedge- a device that is thick on one end and tapers to a thin edge at the other end. It is a movable inclined plane. Example: ax, zipper Mechanical Advantage: length of wedge width of wedge

6. Screw Screw – an inclined plane wrapped around a cylinder
The threads of a screw act like an inclined plane to increase the distance over which you exert an input force.
The closer the threads of a screw the greater the mechanical advantage.
Mechanical advantage – the length around the threads
the length of the screw

8. Levers
Lever- a rigid bar that is free to pivot, or rotate on a fixed point.
The fixed point is called the fulcrum.
Example: Paint can opener
Mechanical advantage = distance from fulcrum to input force
distance from fulcrum to output force

9. 1st class levers
Fulcrum is between input force and output force (object) Examples: see-saw, scissors, crowbar

10. 2nd class levers
Output force (object) is between the fulcrum and the input force. Examples: wheelbarrows, doors, nutcrackers

11. 3rd class levers
Input force is between the output force (object) and the fulcrum Examples: shovel, fishing pole, your arm

12. Wheel and axle
Wheel and Axle- two circular or cylindrical object fastened together that rotate about a common axis. Examples: Ferris wheels, bicycles, door knobs, screw driver Mechanical Advantage = radius of the wheel radius of axle

13. Pulleys
Pulley- a grooved wheel with a rope or cable wrapped around it.
Input force is applied by pulling on one end of the rope which;
Decreases the amount of input force needed by applying it over the distance of the rope
Can change the direction of your input force
Ex. flagpole

14. Types of Pulleys
Fixed pulley – a pulley attached to a stationary structure; only changes direction of the force Mechanical Advantage = 1 Movable pulley – multiplies input force, but does not change direction Mechanical Advantage >1 Block and Tackle – system made up of fixed and moveable pulleys

15. Increasing Mechanical Advantage of a pulley
The longer the rope the longer the distance the input force is applied over, so the greater the mechanical advantage. Mechanical Advantage of a pulley system = the number of supporting sections of a rope

17. Compound Machines
A combination of two or more simple machines Ex. Apple peeler