The useful power is 10 kW, how much water can the pump lift from a depth of 18 meters for 8 hours.

Initial data: N (useful power of the pump) = 10 kW = 10 * 10 ^ 3 W; h (the height to which the water must be raised) = 18 m; t (pump running time) = 8 h = 8 * 3600 s = 28800 s.

Constants: ρ (water density) = 1000 kg / m3; g (acceleration due to gravity) = 10 m / s2.

Net power: N = A / t, where A (pump operation when lifting water) = Ep1 – Ep2 = Ep1 – 0 = m * g * h = ρ * V * g * h.

N = ρ * V * g * h / t, whence V = N * t / (ρ * g * h) = 10 * 10 ^ 3 * 28800 / (1000 * 10 * 18) = 1600 m3.