a box of treasure with a mass of 92 kg and volume of 0.031metrecubic lies at the bottom of the ocean.how much force is needed to lift it?

1 answer

Archimedes principle states that the buoyant force equals the weight of fluid displaced.

Fresh water has a density of
ρ=1000 kg/m³

Sea water from deep in the ocean has a mass density of ρ=1050 kg/m³.
Average sea water has a mass density of ρ=1030 kg/m³.

Net force to lift the object
=(m-ρv)g
=(92-ρ*0.031)*9.81 N

Do not forget that to "land" the object on the boat, the buoyant force does not apply any more when the object is in the air.