According to Archimedes' Principle, what is the buoyant force on a submerged object equal to?

• A. The weight of the fluid displaced by the object
• B. The weight of the object
• C. The mass of the object divided by depth
• D. The density of the surrounding water

Answer: (A)

Archimedes' Principle says the buoyant force on a submerged object equals the weight of the fluid the object displaces. In formula form, that’s F_b = ρ_fluid × V_displaced × g, where ρ_fluid is the fluid density, V_displaced is the submerged volume, and g is gravity. This shows buoyancy arises from pushing aside fluid: the more fluid you displace (larger submerged volume) or the denser the fluid, the greater the buoyant force.

That’s why the statement in question is correct: the upward force matches the weight of the displaced fluid, not the object's weight or some unrelated quantity. The object’s weight is a downward gravitational force, not the buoyant force. A simple mass divided by depth isn’t a relevant measure for buoyancy, and while the fluid density is part of the calculation, density alone doesn’t determine the force without considering the displaced volume and gravity.