Presentation on theme: "Levers and Pulleys Not so simple machines!. Just think…. Could you lift your science teacher in the air?"— Presentation transcript:
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
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