Hollow iron sphere is half submerged in water.Sphere has outer diameter of 10 cm. Calculate thickness of the wall , when the iron density is 7.9 g / m3.
I get answer 0.11cm, book says that it is 0.22cm.
The Attempt at a Solution
First i found buoyant force F=ρgV/2 where ρ is density of water and V is volume of a sphere.
Then I found mass of a sphere : ρgV/2=mg
I know density of iron ,so: 7900=0.26/v where v is volume of the wall
(v= volume of outside sphere - volume of inside sphere.)
From there I get thikness of the wall to be 0.11cm.