Question

how much time will a pump of 1kw power take to lift 500 L of water to a height of 40 m given density of water is 1 kg / litre and g = 10 metre per second square

Answer 1

energy = mgh
=500 x 10 x 40
=2 x 10^5 joule

here ,
mass =volume x density
=500L x 1 kg/L=500 kg

time =energy /power
=2 x 10^5/10^3 = 2 x 10^2 sec