Question

How long does a 50 kW pump motor have to run to pump 500 cubic meters of water from a 180m deep mine.

Answer 1

$mgh=Pt\to\rho Vgh=Pt\to$

$t=\rho Vgh/P=1000\cdot500\cdot9.8\cdot180/50000=17640(s)=4.9(h)$