Simple MachinesSimple Machines

Simple MachinesSimple Machines

Machines are tools that make jobs Machines are tools that make jobs easier by:easier by:Changing the size of the forceChanging the size of the forceChanging the direction of the forceChanging the direction of the forceIncreasing the speed or distance Increasing the speed or distance

the object is movedthe object is moved

Simple MachinesSimple Machines Inclined planeInclined plane

WedgeWedge

ScrewScrew

Simple MachinesSimple Machines

LeverLever

PulleyPulley

Wheel Wheel & Axle& Axle

Mechanical AdvantageMechanical Advantage

MA is the number of times a machine MA is the number of times a machine multiplies the force being appliedmultiplies the force being applied

Ideal mechanical advantage (IMA) is Ideal mechanical advantage (IMA) is the number of times the applied force the number of times the applied force is multiplied under ideal conditions. is multiplied under ideal conditions. This assumes no friction!This assumes no friction!

Mechanical AdvantageMechanical Advantage

Actual mechanical advantage (AMA) Actual mechanical advantage (AMA) is the number of times the applied is the number of times the applied force is multiplied under real force is multiplied under real conditionsconditions

Calculating IMACalculating IMA

Calculating IMACalculating IMA

dR=rampHeight=2m

ddEE=ramp length=10m=ramp length=10m

For a ramp 10m long and 2m high:

Calculating AMACalculating AMA

Calculating AMACalculating AMA

EfficiencyEfficiency

EfficiencyEfficiency

Word ProblemsWord Problems

RTDQ – Read the darn question!RTDQ – Read the darn question!What is the question asking me to What is the question asking me to

find?find?What information do I have in the What information do I have in the

problem? Draw a picture!problem? Draw a picture!If I don’t have enough information, is If I don’t have enough information, is

it a two-step problem?it a two-step problem?