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A machine = a device that helps us toovercome a load with less
effort of force.Sometimes a machine is called a
forcemultiplier.
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Devices which are classed as simple
machinesare:LeverPulleyWedgeScrewInclined planeWheel and axle
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Complex machines such asandconsist ofA machine helps us to do a
job fasterwith less effort
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Levers are commonly used in everyday life.Levers can be
classified into three classes:
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The fulcrum is between the load and the effort.The load and the
effort act in the same
direction.Advantage = a small effort can lift a heavyload if the
effort arm is longer than the load
arm.Examples :
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Fulcrum
Loadffort
Fulcrum
Load
EffortFulcrum
Load
Effort
FulcrumLoad
Effort
FulcrumLoad Effort
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The load is between the fulcrum and theeffort.The load and the
effort act in oppositedirections.Advantage = the effort is always
lessthan the load.Examples :
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Fulcrum
Load Effort
Fulcrum
Load
Effort Fulcrum
LoadEffort
Fulcrum
Load
Effort
Fulcrum Load Effort
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The effort is between the fulcrum and the load.The load and the
effort act in opposite
directions.Advantage = a short distance moved by theeffort makes
the load move through a longer
distance.Examples :
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Fulcrum
Load
Effort
Fulcrum
Load
Effort
Fulcrum
Load
Effort
Fulcrum
Load Effort
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Fulcrum
Load
Effort
Fulcrum
Load
Effort
Fulcrum
Load
Effort
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Attention !!
The load arm is the distance from the load tothe fulcrum.The
effort arm is the distance from theeffort to the fulcrum.
Load Load arm = Effort Effort arm
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2N
30 cm
80 cm
Effort
What effort is required to keep the lever in a
horizontalposition?
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1 m
Load
60 cm
Effort 4N
Calculate the weight of the load.
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A force can be used to produce aturning effect to do work.For
example, a nut can be tightenedor loosened with a turning
effect
using a spanner.It would be much easier if thespanner has a
longer handle.
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is called themoment of force.The turning effect can be increased
in twoways:Increase the applied forceMove the force further away
from theturning point.
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The moment of a force is defined as :
The moment of a force can be clockwise oranticlockwise,
depending on which waythey turn.
Force (N) Perpendicular distance fromthe turning point (m)
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Moment about a pivot
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Moment about a pivot:
