Question

a black of mass 92 kg and volume 0.031 lies at the bottom of the sea how much force is needed to lift it ? take 1.03*10^3 kg/m as the density of sea water

Answer 1

"Any object, wholly or partially immersed in a fluid, is buoyed up by a force equal to the weight of the fluid displaced by the object." - Archimedes of Syracuse

Given:
g = 9.8[m/s^2]
ρ = 1.03e+3 [kg/m^3]
m = 92[kg]
V = 0.031[m^3 ?] ...check volume units.
Use:
F = (m - ρV)g

Answer 2

588N