Efficiency Calculation of a Machine
What is the efficiency of a machine that is supplied energy at a rate of 4,000 W and does useful work at a rate of 3,760 W?
Choose the correct answer:
B. 97 percent
C. 92 percent
D. 94 percent
Answer: 94 percent
When calculating the efficiency of a machine, you divide the amount of useful work by the amount of energy supplied. In this case, the machine is supplied energy at a rate of 4,000 W and does useful work at a rate of 3,760 W.
Therefore, the efficiency can be calculated as follows:
Efficiency = (Useful work / Energy supplied) x 100%
Efficiency = (3,760 / 4,000) x 100%
Efficiency = 0.94 x 100%
Efficiency = 94%
So, the efficiency of the machine is 94 percent.