# >> K-12 >> K-12 Basics

How to Calculate the Efficiency of a Simple Machine

There are six types of simple machines: the lever, incline, wheel and axle, wedge, pulley and screw. The efficiency of one of these machines is determined by how much more work is put into operating it than the work done by the machine. Efficiency can never be over 100 percent, since a machine will never do more work than what was put into it. The closer to 100 percent, the more efficient a machine is. Reaching 100 percent is ideal because this means that the work input is equal to the work output --- but this is an impractical goal in the real world.

Instructions

- 1
  Calculate the work put into the machine by multiplying the force needed to operate it by the distance the simple machine has moved an object, for example, pushing a box up a ramp. Force is measured in Newtons. Multiply the force by the distance to get the work input in joules.
- 2
  Calculate the work output of the machine by multiplying the distance moved by the force without the machine, that is, force needed to move the box vertically without using a ramp.
- 3
  Divide the work input by the work output.
- 4
  Multiply this number by 100 to get the efficiency of the machine. The resulting number is the efficiency percentage.

Characteristics of a Cone

How to Estimate With Two-Digit Divisors