Mechanical Advantage and Efficiency 

• Machines make work easier
  • It multiplies the amount of force you exert,
  • It multiplies the distance over which you exert your force,
  • It changes the direction in which you exert your force.
• A machines mechanical advantage is the number of times a force exerted on a machine in multiplied by the machine.
  • Input Force is the amount of force you exert on the machine.
  • Output Force (resistance force) is the amount of force exerted by the machine.
  • Mechanical Advantage = Output Force / Input Force   (MA=OF/IF
• The efficiency of a machine compares the output work to the input work.
  • Efficiency of a machine is expressed as a percent.
  • The higher the percent, the more efficient the machine.
  • NO machine is 100% efficient due to friction.
• The mechanical advantage that a machine provides in a real situation is called the actual mechanical advantage (AMA).
  • AMA can only be gotten by measuring true input and output.
  • The mechanical advantage of a machine without friction is called the ideal mechanical advantage (IMA) of the machine.