# Levers and Pulleys Not so simple machines!. Just think….  Could you lift your science teacher in the air?

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Levers and Pulleys Not so simple machines!

Just think….  Could you lift your science teacher in the air?

Keep Thinking….. (This means you don’t have to write this!!)  Building a house  Lifting a car  Building the pyramids  Handicap ramps  Paper cutters  Wheels on a car  What do all of these have in common?  They are use simple machines!

Important Definitions  Machine- device for doing work  Complex machines have motors, simple machines do not  Effort- the amount of force applied to a machine  Effort is measured in Newtons (N)

Types of Simple Machines  Lever  Pulley  Wheel and axle  Inclined plane  Wedge  Screw

Just Read… Simple machines have been used for thousands of years. They were even used to help build the pyramids!

Levers The most simple and most common simple machine.

3 Parts of a lever

Class 1 Levers

 The fulcrum is located somewhere between the effort and the load  Examples include:  The claw of a hammer  crowbar

Double Class 1 Levers  Two levers working together form a double lever  Examples Include:  Scissors  Tin snips

Class 2 Levers

 Has a fulcrum at one end of the lever arm  Examples include:  Paper cutter  Wheelbarrow

Class 3 Levers

 In a class 3 lever, the fulcrum is at one end, and the effort is applies between the fulcrum and the load  Examples include:  Baseball bat  Fishing pole  Catapult

Wheel and Axle

 Can be an actual wheel and axle OR a bar that rotates around an axis  Examples include:  Steering wheel  A wrench turning a bolt (see levers and pulleys book page 7)  Windlass (crank used to raise a bucket, see page 8)  Handle of a faucet (page 8)

The Inclined Plane

 A sloped, flat surface, or ramp  One-part simple machine that does not move

Pulleys

 A pulley is a wheel that is free to turn on an axle  The wheel is called a sheave  A pulley is considered to be a variation of the lever  Pulleys can be fixed or movable

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