Efficiency measures how much of the work put into a machine is converted into useful work output. Because of friction, no real machine is

No machine is perfect; some energy is always lost to friction, heat, or sound. Efficiency measures the percentage of work input that is successfully converted into useful work output. Efficiency can never exceed 100% in the real world.

No machine is perfect. Efficiency compares the work you get out to the work you put in.

Mechanical advantage describes how much a machine multiplies the input force. There are two ways to calculate this: Ideal Mechanical Advantage (IMA)

The following answer key is derived from a common worksheet for this textbook section. The questions are designed to test your understanding.

$$Efficiency = \fracoutput\ workinput\ work \times 100%$$