1. Simple Machines Week 8 Notes
Chapter 4, Section 3
Pages 124 – 135

2. Simple Machines There are __6__ basic kinds of simple machines.
The __INCLINE PLANE__, the __WEDGE__, the __SCREW__, the __LEVER__, the __WHEEL AND AXLE__, and the __PULLEY__.

3. Inclined Plane How it Works Mechanical Advantage
An inclined plane is a __FLAT, SLOPED SURFACE__
How it Works
An incline plane allows you to __EXERT__ your __INPUT FORCE__ over a longer distance.
Input Force is __PUSHING or PULLING__ up the incline plane
Output Force is the force needed to __LIFT__ the object
Output Force is equal to the __WEIGHT__ of the object
Mechanical Advantage
M.A. = __LENGTH OF INCLINE__ / __HEIGHT OF INCLINE__
The __LONGER__ the incline, the __LESS__ input force you need to __PUSH__ or __PULL__ an object.
Brain Pop: Inclined Plane (1:59)

4. Wedge How it Works Mechanical Advantage
A __WEDGE__ is a device that is __THICK__ at one end and tapers to a __THIN__ edge at the other end.
A wedge can be thought of as __2__ __INCLINED PLANES__
How it Works
Using a wedge, __INSTEAD__ of moving an object along an __INCLINE PLANE__, you __MOVE__ the incline plane itself.
Input Force is the wedge __MOVING__. Output Force is at a __90__ angle to its slope.
Mechanical Advantage
M.A. = __LENGTH OF WEDGE__ / __WIDTH OF WEDGE__
The __LONGER__ and __THINNER__ the wedge is, the __GREATER__ the M.A.
(1:26)

5. Screws
A __SCREW__ can be thought of as an __INCLINED PLANE__ wrapped around a cylinder.
How it Works
__TWISTING__ a screw you are __EXERTING__ an __INPUT FORCE__ on the screw.
The __THREADS__ on a screw exert an __OUTPUT FORCE__ on the object, __PULLING__ the screw into the material.
__FRICTION__ between the __SCREW__ and the __MATERIAL__ holds the screw in place.
Mechanical Advantage
M.A. = __LENGTH AROUND THE THREADS__ / __LENGTH OF THE SCREW__
The __CLOSER__ the threads are the __GREATER__ the mechanical Advantage.
Eureka! Screw (1:35)

6. Levers How it Works Mechanical Advantage
A __LEVER__ is a rigid bar that is free to __PIVOT__, or rotate, on a fixe point
The fixed point that a lever pivots around is called the __fulcrum__
How it Works
On the end of a __LEVER__ that you push down, you exert an __INPUT FORCE__
The lever pivots on the __FULCRUM__
The other side of the lever pushes up, as the __OUTPUT FORCE__
Mechanical Advantage
M.A. = __DISTANCE FROM FULCRUM TO INPUT FORCE__ / __DISTANCE FROM THE FULCRUM TO OUTPUT FORCE__

7. Different Types of Levers
Levers are classified by the __LOCATION__ of the __FULCRUM__
1st Class Levers
__ALWAYS__ change the direction of the input force
In order: __OUTPUT FORCE __ __FULCRUM__ __INPUT FORCE __
2nd Class Levers
__INCREASE FORCE__, but do not change the direction of the input force.
In order: __INPUT FORCE __, __OUTPUT FORCE __, __FULCRUM__
3rd Class Levers
__INCREASE DISTANCE__, but do not change the direction of the input force.
In order: __FULCRUM__ __INPUT FORCE __ __OUTPUT FORCE __

8. Levers in the Body
Brain Pop: Levers (2:40)

9. Wheel and Axle How it Works Mechanical Advantage
__2__ circular or cylindrical objects fastened together that __ROTATE__ about a common axis.
Larger radius is called the __WHEEL__
Smaller radius is called the __AXLE__
How it Works
The __INPUT FORCE__ is exerted into the __WHEEL__
The __AXLE__ rotates and exerts a large __OUTPUT FORCE__
Mechanical Advantage
M.A. = __RADIUS OF WHEEL__ / __RADIUS OF AXLE__
__RADIUS__ is the distance from the __OUTER__ edge of a circle to the circle’s __CENTER__
Brain Pop: Wheel and Axel (1:42)

10. Pulley
A __PULLEY__ is a simple machine made of a grooved wheel with a rope or cable wrapped around it.
How it Works
__PULL__ on one end of rope = __INPUT FORCE__
__OUTPUT FORCE__ pulls up on the object you want to move
Can __DECREASE__ the amount of input force needed to lift the object
Can __CHANGE__ the direction of your input force.

11. Types of Pulleys
__FIXED PULLEY__ does not change the amount of force applied. __CHANGES__ direction
__MOVABLE PULLEY__ decreases the amount of __INPUT FORCE__ needed. __DOES NOT__ change direction
__BLOCK AND TACKLE__ is a system made up of __FIXED__ and __MOVABLE__ pulleys
M.A. is __EQUAL__ to the __NUMBER__ of sections of rope that support the object.
Brain Pop: Pulley (2:09)

12. Compound Machines
__COMPOUND MACHINES__ is a machine that utilizes __2__ or __MORE__ simple machines.