Question

Kevin used a pulley to lift a piano to the third floor of his apartment. His input work was 12,000 J and the output work was 10,000 J. What was the mechanical efficiency of the pulley?

A . 50%
B. 83.3%
C . 120%
D. 16.7%

Answer 1

B

Step-by-step explanation:

Eff = output work/input work ×100

Hence, Eff = 10000/12000 × 100

Eff = 83.3%