Question

which is the equation for a machines efficiency? (1 point)
efficiency = \frac{input energy}{output energy} \cdot 100
efficiency = input energy + output energy
efficiency = \frac{output energy}{input energy} \cdot 100
efficiency = input energy - output energy

Explanation:

Efficiency is a measure of how well a machine converts input energy into useful output energy. It is calculated as the ratio of output energy to input energy, multiplied by 100 to get a percentage. The formula \(Efficiency=\frac{output\ energy}{input\ energy}\cdot100\) reflects this concept. The other options are incorrect: adding input and output energy (\(Efficiency = input\ energy+output\ energy\)) does not represent efficiency; subtracting (\(Efficiency = input\ energy - output\ energy\)) gives energy loss, not efficiency; and having input over output (\(Efficiency=\frac{input\ energy}{output\ energy}\cdot100\)) is the inverse of the correct relationship.

Answer:

Efficiency = \(\frac{output\ energy}{input\ energy}\cdot100\) (the third option).