When asked for the bouancy of a hollow cylinder, containing air, submerged in ocean water.
outer radius R.
Length of cylinder = L
The Material of the cylinder is neglected.
I'm thinking the Bouancy (Force) = ρ ⋅ g ⋅ v
where v = LπR^2 and therefore F = ρgLπR^2
But the solutions manual states it is
F = ρgLπR^2 ⋅ SG, where SG is Specific gravity of ocean water.
Why do I need the SG part ?