JAMB - Physics (2025 - No. 20)
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\(^{-2}\)?
100W
1000W
250W
40W
Giải thích
Answer: B. 1000W
(Fixed pulley: force = mg = 200 N; power = F × v = 200 × 5 = 1000 W.)