Robot? I think yes!

Simple MachinesSimple Machines

A group of six basic types that combine to A group of six basic types that combine to make more complex machines.make more complex machines.

They allow work to be done with less forceThey allow work to be done with less force

Simple machines are divided into two Simple machines are divided into two families:families:

The Lever FamilyThe Lever Family

The Inclined Plane FamilyThe Inclined Plane Family

The Lever FamilyThe Lever FamilyAll levers are composed of a All levers are composed of a FULCRUMFULCRUM and an and an ARMARM..

ArmArm – the rigid portion of the lever – the rigid portion of the lever

FulcrumFulcrum – the point the lever pivots on – the point the lever pivots on

Force is transferred along the arm causing Force is transferred along the arm causing the input force to be multiplied or the input force to be multiplied or redirectedredirected

There are 3 classes of levers:There are 3 classes of levers:First Class LeverFirst Class Lever – – the most common the most common typetype

- Input force is at one end and the output- Input force is at one end and the output

force is at the other end at the otherforce is at the other end at the other

Examples:Examples: hammer and pliers (2 1 hammer and pliers (2 1stst class class levers combined)levers combined)

Second Class LeversSecond Class Levers – – the input force is the input force is applied at one end with the fulcrum at the applied at one end with the fulcrum at the otherother

Examples:Examples: Wheelbarrow and nutcracker Wheelbarrow and nutcracker

Third Class LeversThird Class Levers – – multiply distance multiply distance rather than force (decreases the distance rather than force (decreases the distance the force needs to move)the force needs to move)

Examples – Examples – human forearmhuman forearm

Pulleys are Levers Too!Pulleys are Levers Too!

The point in the middle of a pulley is like The point in the middle of a pulley is like the fulcrum in a 1the fulcrum in a 1stst class lever class lever

Therefore pulleys act like 1Therefore pulleys act like 1stst class levers class levers

Multiple pulleys can be combined and are Multiple pulleys can be combined and are called a called a Block and TackleBlock and Tackle

The Inclined Plane FamilyThe Inclined Plane FamilyInclined planes decrease the amount of Inclined planes decrease the amount of force required by spreading the work done force required by spreading the work done over a larger distanceover a larger distance

Pushing up a long ramp that climbs slowly Pushing up a long ramp that climbs slowly is easier than up a short steep rampis easier than up a short steep ramp

Examples of Inclined PlanesExamples of Inclined PlanesWedgeWedge – – a modified inclined plane that turns a modified inclined plane that turns one downward force into two forces directed one downward force into two forces directed sidewayssideways

- Examples: nail and axes- Examples: nail and axes

ScrewScrew – – an inclined plane wrapped around a an inclined plane wrapped around a cylindercylinder

- a gentle sloped screw requires less force than- a gentle sloped screw requires less force than

a steeper sloped screw (JUST LIKE A RAMP!!)a steeper sloped screw (JUST LIKE A RAMP!!)

Compound MachinesCompound Machines

A machine that combines two or more A machine that combines two or more simple machinessimple machines

Examples:Examples:

- - scissors (2 1scissors (2 1stst class levers) class levers)

- - car jack (lever and large screw)car jack (lever and large screw)

- - car (lots of simple machines)car (lots of simple machines)