Mechanical Advantage

MA = Output Force (N) = Load Force (F1)  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  Input Work = the work you do on the machine  Output Work = the work the machine does on the load  MA = Output Force (N) = Load Force (F1) Input Force (N) Effort Force (F2) 

Examples of mechanical advantage BLM 4-4

The Mechanical Advantage of using a lever MA = Effort Arm Length Load Arm Length

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 Axle Effort Arm 1 cm

The Mechanical Advantage for a Gear Wheel MA = Number of driving gear teeth Number of driven gear teeth (load) MA = 60 = 1.5 40 Driving Gear 60 Teeth Driven Gear 40 Teeth

If Mechanical Advantage = 1 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