W = (pi)r^2Hgi
W = mad (mass x acceleration x distance), so W=(pi)r^2h)9.8(I)
Volume of cylinder is (pi)r^2h
But actually I'd do, W=(pi)r^2h)9.8(I+h) and fill the tank from the top....otherwise the force require to fill from bottom would change as u fill the tank.....