How to calculate the time for given information?

Question

calculate time for which a motor pump of 10HP and efficiency 80% be switched on so as to pump 20m3 of water through a vertical height of 20m[density of water=1000kgm-3,g=10ms-2,1HP=750] iwant to be answer 666.67s

Answer 1

Mass m = volume * density = 20*1000 = 20,000 kg

Height h = 20 m

Work is done against gravity.

Work done = mgh = 20,000 * 10 * 20 = 4 * 10^6 Joule

Motor pump has power of 10HP and efficiency of 80%.

So, effective power = 80% if 10 HP = 10 * 80/100 = 8 HP

1 hp = 750 W

Therefore, effective power = 8 * 750 W = 6,000 W

Time = work done/effective power

= 4*10^6/6000 sec = 4*10^3/6 sec = 4000/6 sec = 2000/3 sec = 666.67 sec

Answer 2

efficiency*power of pump = m*g*h

efficiency*E/t = density of water*volume*g*h

80%*10*750/t = 1000*20*10*20

t = (80%*10*750)/(1000*20*10*20)

t = 0.0015 sekon

Answer 3

Please remember that, When one pump  Lift water from a water sorcs The time is depend upon its headers pipe lenth  pipes dieas,RPM,delivery pipes dieas n lenth,vatical or horizenal,Hight or defth and bend open pipes. Exmp.- One 0.5 HP pumps (Sharp Big Flow).When Head is 10ft vertical,RPM-2800,Delivery Pipe leanth With hight 50ft ,Pipe Diea -1",Less bend upon pipe.Then you find 4500Lter/Hour. Thank You