[graciele]

Okay, I just want to know when does a submarine experience greater buoyant force? Is it when it is near the surface of the ocean or near the ocean floor, considering gravity is the same for both situations.

[rajeevsrai]

Buoyant forces are more at surface.

[Capuchin]

The buoyant force is only proportional to the submerged volume of the object, with the net force felt by the object being the Force due to gravity - the buoyant force.

It does not vary with depth unless the density of the water does, if the density increases then the buoyant force does also.

[rajeevsrai]

buoyant forces are more at surface.

I suppose the submarine are different than simple objects. Net force will be gravity minus upward thrust. At the surface wieght of sub is less because of air filled in. at a depth water is allowed so net upward force is reduced.

[Capuchin]

Ah, I missed that it was a submarine! But the amount of air is independent of depth. The amount of air is used to accelerate up or downwards, not to determine position in the water.