Question

calculating efficiency
two movers use a rope system to lift a box to a third - story apartment. they do 1200 j of work on the rope system and the rope system does 1020 j of work on the box. what is the efficiency of the rope system?
the efficiency of the rope system is ______ %.

Explanation:

Step1: Recall efficiency formula

Efficiency = $\frac{\text{Useful Work Output}}{\text{Total Work Input}} \times 100\%$

Step2: Identify given values

Useful Work Output = 1020 J, Total Work Input = 1200 J

Step3: Substitute values into formula

Efficiency = $\frac{1020}{1200} \times 100\%$

Step4: Calculate the result

$\frac{1020}{1200} = 0.85$, $0.85 \times 100\% = 85\%$

Answer:

85