Work efficiency uses a ratio to determine how efficiently a machine operates. The less waste in the operation, the better the efficiency. A perfect work efficiency of 1 means that every unit of work put into the machine produces an equal outcome. Solve the work efficiency as either a decimal or a percentage to see how well a machine works.
Find the work put into the machine by multiplying the force in pounds put into the machine to operate it by the distance traveled in feet required to apply that force. For instance, suppose a person has to apply 6 pounds of force to pull a pulley rope 2 feet to lift a 10-pound weight 1 foot off the ground. Multiply 6 lbs. x 2 feet = 12 foot-pounds. This is the work input.
Multiply the weight of the object by the distance it traveled to find the amount of work output. For the example: 10 lbs. x 1 foot = 10 foot-pounds.
Find the work efficiency by dividing the work output by the work input and multiplying by 100. For the example, the pulley would have a work efficiency of 10/12 = 0.833 x 100 = 83.3 percent work efficiency.
- pulley of a boat image by timur1970 from Fotolia.com