According to the law of buoyancy, the buoyant force on a body submerged in water equals what?

• A. The weight of the water displaced
• B. The weight of the body
• C. The volume of water displaced
• D. The density of water

Answer: (A)

Buoyant force follows Archimedes’ principle: the upward push on a submerged object equals the weight of the fluid it displaces. In water, that means the buoyant force is the weight of the water volume that has been pushed aside by the object. Mathematically, it’s ρ_water × g × V_submerged, so the force is determined by how much water is displaced and how heavy that water is.

That’s why the correct interpretation is the weight of the displaced water. The weight of the body isn’t the buoyant force—it’s what helps determine whether the object sinks or floats, but the buoyant force itself depends on displaced water. The volume displaced is a volume (not a force), and the density of water alone isn’t a force either; it combines with gravity and displaced volume to give the buoyant force.