A machine is used to lift a load of 20 N through a height of 10 m. if the efficiency of the machine is 40%, how much work is done?
A
80 J
B
500 J
C
300 J
D
120 J
Verified Correct Answer: B.
Physical Principles & Numerical Solution
Efficiency = \( \frac{\text{work output}}{\text{work input}} \times \frac{100}{1} \)
= 40 = \( \frac{20 \times 10 }{x} \times \frac{100}{1} \)
= 500J
Source: Myschool Past Questions Archive (Record #14391)