Simple Machines

Machine A device that can do work in a way that is easier or more effective

Force Input force = force exerted on the machine Output force = force exerted by the machine

Force Input Force Output Force

Simple Machines Make work easier

Six Types Inclined Plane LeverScrewPulley Wheel and Axle Wedge

Inclined Plane A flat slanted surface Increases the distance that you exert the force. Examples: ramps, stairs

Wedge Thick at one end, tapers to a thin edge at the other end Turns a single downward force into two forces directed out to the sides Examples: axe blade, nails

Screw An inclined plain wrapped around a cylinder Examples: jar lids, bottle caps

Wheel and Axle Two circular objects that are fastened together and rotate around a common axis. Examples:car steering wheel, wheels and axle of a car, screwdrivers

Pulleys A grooved wheel with a rope,belt, or chain wrapped around it

Levers A rigid arm that turns around a point called the fulcrum. Levers are divided into three classes.

First-Class Levers The fulcrum is between the effort and the load. Examples: a claw hammer, a see- saw, a pair of pliers, scissors.

Lever Fulcrum (pivot) (load) effort First Class Lever

Second-Class Levers The load is between the fulcrum and the effort. Examples: a wheelbarrow, door on hinges, bottle opener, stapler.

Lever Fulcrum (pivot) load effort Second-Class Lever

Third-Class Levers The effort is between the fulcrum and the load. Examples: the human forearm, tweezers, tongs, fishing rod.

Lever Fulcrum (pivot) load effort Third-Class Lever