Levers

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Levers
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• Leverage is the use of a mechanical advantage to
  
• Overcome resistance
• Create balance
• Exert force or power
• Increase speed
• Increase range of motion

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Lever definition a rigid bar that turns about
an axis of rotation, or a fulcrum.
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All lever systems three components

• Fulcrum axis
• 2.Effort force
• 3.Resistance

joint
muscles
the weight lifted resistance of gravity
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3 types of levers found in the human body
1st Class 2nd Class 3rd Class
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The arrangement or location of E F R in relation
to one another determine the type of lever and
for which kind of motion it is best suited.
E
F
R
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1st class lever When the Fulcrum is placed
between the Effort and the resistance
Designed for balance
http//www.usoe.k12.ut.us/curr/science/sciber00/8t
h/machines/sciber/lever1.htm
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1st class lever
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2ND Class lever When the resistance is between
the fulcrum and the effort
Designed for power
http//www.usoe.k12.ut.us/curr/science/sciber00/8t
h/machines/sciber/lever2.htm
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2ND Class lever
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3rd Class lever When the Effort is between the
Fulcrum and the Resistance
Designed for speed and range of motion
http//www.usoe.k12.ut.us/curr/science/sciber00/8t
h/machines/sciber/lever3.htm
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3rd Class lever
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Memory Clue 1EFR (first-class, effort, fulcrum,
resistance)
Memory Clue 2FRE (second class, fulcrum,
resistance effort)
Memory Clue 3FER (third-class, Fulcrum, effort,
resistance)
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What kind of lever is most prevalent in the body?
Designed for speed and range of motion
3rd class