a pump on the ground floor of a building can pump water to fill the tank of volume 30 m cube in 15 minutes .if the tank is 40 m above the ground and efficiency of the pump is 30% how much electric power is consumed by the pump.mam its really urgent..
Mass of water to be pumped up, m= 30 m3 x 1000 kg/m3 (density of water =1000kgm-3)
Height, h= 40 m; time t =15 minute= 15 x 60 s= 900sec
Required power =mgh/t = (3x 104 x9.8 x 40W)/900
Power consumed = (100/30) x(3x 104 x9.8 x 40W)/900 (as efficiency =30%)
=4.36 x 104 W or 43.6 kW