Question

The radius of a well is 7m.water in it is at a depth of 20m and depth of water column is 10m.work done in pumping out water completely from the well is,(g = 10m/s2)
1)38.5MJ 2)38KJ 3)46.2MJ 4)385MJ

Answer 1

Answer:

Explanation:

w=f*s

force = mass of water

volume of water == 22/7*7*7*10==1540m^3

if water 1000kg/m^3 density

so mass ==1540 000 kg

so work= 1540 000*(total height)

1540 000*(30)

4620000J

1 MJ= 10^6J

SO ANSWER = 46.2 MJ ---- OPTION(3)

Answer 2

Answer:

46.2MJ Option 3 is the right answer