Question

A person uses a simple machine to help him perform a difficult task. He performs 25 J of work on the machine, which performs 22 J of work in return. What is the machine’s efficiency?

a. 11%

b. 88%

c. 90%

d. 110%

Answer 1

The efficiency of the machine is 88%, calculated by dividing the output work of 22 J by the input work of 25 J and then multiplying by 100 to convert it to a percentage.

Step-by-step explanation:

The machine's efficiency is calculated by dividing the output work by the input work and then multiplying by 100 to express the value as a percent. In this case, the student performs 25 J of work on the machine, and the machine performs 22 J of work in return. Therefore, to calculate the efficiency, we use the formula: Efficiency = (Output Work / Input Work) × 100 percent. Inserting the given values, the efficiency is (22 J / 25 J) × 100%, which equals 88%.

Answer: The machine's efficiency is 88%, which corresponds to option b.