Machine Review

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Machine Review
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Inclined Plane
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Pulleys
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Lever
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Classes of Levers
http//www.enchantedlearning.com/physics/machines/
Levers.shtml
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Simple Machines

• Machines help us do work by decreasing the
  Effort Force and increasing the Effort Distance
  needed to do the work.
• Work done remains the SAME! We are lifting the
  same load the same distance!
• L.F. x L.D. E.F. x E.D.

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Load Force Load Distance

• Load Force Force a machine exerts to lift a
  load. When lifted straight up, it is equal to
  the weight of the load.
• Load Distance Distance a load moves when acted
  on by a load force.

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Effort Force Effort Distance

• Effort Force Force exerted by a person (or
  motor) when using a machine to lift a load.
• Effort Distance The distance over which the
  effort force acts in a simple machine.

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Mechanical Advantage

• Ideal Mechanical Advantage
• Effort Distance / Load Distance
• Actual Mechanical Advantage
• Load Force / Effort Force

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Mechanical Advantage

• A High Actual Mechanical Advantage means Little
  effort force is needed to lift a larger load.
• A High Ideal Mechanical Advantage means Larger
  Effort Distance is needed to lift the load the
  load distance.

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Actual vs. Ideal Mech. Adv.

• Actual Mechanical Advantage tends to be less than
  Ideal Mechanical Advantage because of FRICTION!

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Input Work and Output Work

• Output Work
• Load Force x Load Distance
• Define Output Work Work done on the load by a
  simple machine.
• Input Work
• Effort Force x Effort Distance
• Define Input Work Work done by the effort force
  in a simple machine.

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Efficiency

• Efficiency
• Output Work/Input Work x 100
• A high Efficiency means amount of output work is
  very close to amount of input work.
• REMEMBER A machine could have a high mechanical
  advantage, but low efficiency and vice versa.

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Equations

• Work (N-m) Force (N) x Distance (m)
• Input work effort force x effort distance
• Output work load force x load distance
• Power (W) Work (N-m) / Time (s)
• Slope of an Incline Rise / Run
• Ideal Mechanical Advantage Effort Distance /
  Load Distance
• Actual Mechanical Advantage Load Force / Effort
  Force
• Efficiency Output Work / Input Work x 100