Simple Machines

Machine

Any device that helps people do work more efficiently by changing the size or direction of a force

Simple Machines

the most basic mechanical devices

Lever

• Rigid bar that rotates around a fixed called a fulcrum

• Multiplies force, changes direction of force

First Class Lever

Fulcrum between effort and load (seesaw, crowbar, etc.)

Second Class Lever

Load between fulcrum and effort (wheelbarrow, nutcracker, etc.)

Third Class Lever

Effort between fulcrum and load (tweezers, tongs)

Wheel And Axle

• Large fixed wheel fixed to a smaller axle

• Reduces friction, multiplies force

Pulley

Grooved wheel with a rope or chain

Changes direction of force ormreduces effort needed to lift objects

Inclined Plane

Flat, slanted surface

Effort needed to lift objects by increasing distance

Wedge

Two incluned planes joined together

Converts applied force into splitting or cutting action

Screw

Inclined plane wrapped around a cylinder

Converts rotational force into linear force