A boy uses a single string pulley system to lift a mass of 20kg moving with a velocity of 5ms\(^{-1}\). What is the power developed by the boy if g = 10ms\(^{-2}\)?
A
100W
B
1000W
C
250W
D
40W
Verified Correct Answer: B.
Physical Principles & Numerical Solution
Answer: B. 1000W
(Fixed pulley: force = mg = 200 N; power = F \times v = 200 \times 5 = 1000 W.)
Source: Myschool Past Questions Archive (Record #74366)