Download Mechanical Advantage

Mechanical Advantage
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
Mechanical Advantage: the ability for a machine to
make a task easier by reducing the amount of force
required
The ratio of the amount of force produced by a
machine compared to the amount of force you apply

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Input Work = the work you do on the machine
Output Work = the work the machine does on the load
MA = Output Force (N) =
Input Force (N)
Load Force (F1)
Effort Force (F2)
Examples of mechanical advantage BLM 4-4

The Mechanical Advantage of using a lever
MA = Effort Arm Length
Load Arm Length
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The Mechanical Advantage for a Ramp
MA
=
Length of Ramp
Height of Ramp
MA = 30 = 3
10
L = 30 m
H = 10 m

The Mechanical Advantage for a Wheel and Axle
MA
=
Length (or radius) of the Effort Arm
Length (or radius) of the Load Arm
MA = 1 = .17
6
Load Arm
6 cm
Wheel
Effort Arm
1 cm
Axle
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The Mechanical Advantage for a Gear Wheel
MA
=
Driving Gear
Number of driving gear teeth
Number of driven gear teeth (load)
MA = 60
= 1.5
40
60 Teeth
Driven Gear
40 Teeth
If Mechanical Advantage = 1
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
the machine has not increased or decreased the
amount of force applied
May have changed direction of force
Examples: no machine, a fixed pulley, parallel
gears, class 1 lever (Fulcrum in the middle)
If Mechanical Advantage < 1

This usually involves a machine that produces a
speed advantage or a distance advantage
Examples: class 1 lever (fulcrum far from load),
bike, class 3 levers (golf clubs, baseball bats,
hockey sticks)
If Mechanical Advantage > 1


Use of the machine decreases the amount of force
required
A force advantage is gained at the expense of
speed or distance
Examples: class 1 and 2 levers, reducing gears, a
large axle turning a small wheel, an inclined plane