The force of buoyancy on an object floating on water is F, while it is

The force of buoyancy on an object floating on water is F, while it is S on an object that sinks in water. The weight of both the objects is W. Which one of the following is always true?

”F
”Both
”F
”F
This question was previously asked in
UPSC Geoscientist – 2023
The correct answer is B) Both F and S have upward direction.
The force of buoyancy is an upward force exerted by a fluid that opposes the weight of an immersed object. It is caused by the pressure difference between the top and bottom of the object. This force always acts vertically upwards, regardless of whether the object is floating or sinking.
For an object floating on water, the buoyant force (F) is equal to the weight of the object (W), resulting in zero net force and equilibrium. F = W. The object is partially or fully submerged such that the weight of the displaced water equals the object’s weight.
For an object that sinks in water, the buoyant force (S) is less than the weight of the object (W). The net force (W – S) is downward, causing the object to accelerate downwards (sink). S is equal to the weight of the fluid displaced by the fully submerged object. Even though the object sinks, the water still exerts an upward buoyant force on it. Therefore, both F (for floating) and S (for sinking) are upward forces.