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
Explanation
Correct Option
bVideo Explanation
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Velapearl
2 months ago
Given: Mass, m = 20 kg
Acceleration due to gravity, g = 10 m/s²
Velocity, v = 5 m/s
First, we find the weight (force needed to lift the mass):
Weight, F = mg
F = 20 × 10
F = 200 N
Now power is:
Power, P = Force × Velocity
P = F × v
Substitute values:
P = 200 × 5
P = 1000 W
Final answer: 1000 W


