Answer:
The answer to the question is
4433.416 kJ
See explanation below
(3-y)²+r² = 3² or
6y-y² = r²
r =√(6y-y²)
The volume of a small section of height Δy = Δy ×(√(6y-y²))²×π
For water with density of 1000 kg/m³, the mass of the slice
= 1000×Δy ×(√(6y-y²))²×π and since force = mass × acceleration we have
1000×Δy ×(√(6y-y²))²×π ×g = 1000×Δy ×(√(6y-y²))²×π ×9.81
The work done to move a unit height of y+1 = Force × Distance
W = 1000×Δy ×(√(6y-y²))²×π ×9.81 × (y+1)
Integrating the entire section of the sphere that is 2×r high, or from 0 to 6 we get
W =[tex]\int\limits^6_0 {1000*(6y-y^{2} ) *\pi *9.81 * (y+1)} \, dy[/tex]
= [tex]9810*\pi \int\limits^6_0 {5y^{2} -y^{3} +6y \, dy[/tex]
[tex]= 9810*\pi *[\frac{5y^{3} }{3} -\frac{y^{4} }{4} +3y^{2} ]^{6} _{0}[/tex]
=9810×π×144 =4433416 J
