JEE Main Physics question
A coolie 1.5 m tall raises a load of 80 kg in 2 s from the ground to his head and then walks a distance of 40 m in another 2 s. The power developed by the coolie is (g = 10 ms⁻²)
Answer: (C)
Solution
Work in lifting = mgh = 80×10×1.5 = 1200 J (the subsequent horizontal walk does no work against gravity). Power = 1200/2 = 600 W = 0.6 kW.