Making WORK easier!Making WORK easier!

Types of Simple MachinesTypes of Simple Machines

LeverLever

ScrewScrewWedgeWedge

Inclined PlaneInclined PlanePulleyPulley

Wheel and Wheel and axleaxle

Why do we use them?Why do we use them?

Machines make work easier (NOT less) by Machines make work easier (NOT less) by changing either the:changing either the:

Direction of the forceDirection of the forceSize of the forceSize of the force

50 kg

Mechanical AdvantageMechanical AdvantageThe number of times a machine multiplies your The number of times a machine multiplies your

applied force is the ACTUAL mechanical advantgeapplied force is the ACTUAL mechanical advantge

M.A. = Fr

Fe

Resistance Resistance Force (weight Force (weight of object)of object)

Effort Force Effort Force (force YOU are (force YOU are supplying)supplying)

Mechanical Mechanical AdvantageAdvantage

Effort ForceEffort Force

FFee

Resistance ForceResistance Force

FFrr

Ideal Mechanical AdvantageIdeal Mechanical Advantage

The number of times a machine SHOULD The number of times a machine SHOULD multiply your applied forcemultiply your applied force

I.M.A. = I.M.A. = depends on type of depends on type of machinemachine

Ideal Mechanical Ideal Mechanical AdvantageAdvantage

Measure of how much work put into aMeasure of how much work put into a

machine is changed to useful work put outmachine is changed to useful work put out

by the machine.by the machine.

M.A.

I.M.A.Efficiency = X 100

EfficiencyEfficiency

WorkWork

Energy is conserved Energy is conserved in “ideal” in “ideal” machines, the work you put in is equal to machines, the work you put in is equal to the work the machines gives outthe work the machines gives out

““Real” machines Real” machines you do MORE work you do MORE work than machines give back outthan machines give back out

Why use them???Why use them???

W = FW = F··dd W = W = FF··dd

Parts of a leverParts of a lever

Fr

Feddrr

ddeeFulcrumFulcrum

Resistance distanceResistance distance

Effort distanceEffort distance

Three classes of LeversThree classes of Levers11stst class lever class lever 22ndnd class lever class lever

33rdrd class lever class lever

Mechanical Mechanical Advantage is Advantage is LESSLESS than 1 than 1

FulcrumFulcrum

Effort ForceEffort Force

Resistance Resistance ForceForce

Which class lever?Which class lever?

IMA - LeversIMA - Levers

The number of times a lever SHOULD The number of times a lever SHOULD multiply your applied forcemultiply your applied force

I.M.A. = dI.M.A. = dee

ddrr

Resistance Resistance distancedistance

Effort Effort distancedistance

Inclined planeInclined plane

FFrrFe

WWoutout = = FFrr··ddrr

WWinin = = FFee··ddee

Ideal Mechanical Advantage - Ideal Mechanical Advantage - Inclined PlaneInclined Plane

IMA = LIMA = L

hhLL

hh

Big Bang Theory clip

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