Which statement best describes Archimedes’ principle?

• A. A body immersed in water is buoyed by a force equal to the weight of the water displaced
• B. Buoyant force equals the weight of the body
• C. Buoyant force equals the volume of water displaced
• D. Buoyant force equals the density of water times gravity

Answer: (A)

Archimedes' principle says the buoyant force acting on a submerged or partially submerged body equals the weight of the fluid it displaces. This upward push comes from the pressure difference in the fluid: pressure at depth is greater, so the bottom surface experiences more force than the top, resulting in a net upward force. Mathematically, the buoyant force is F_b = ρ_fluid × V_displaced × g, where ρ_fluid is the fluid density, V_displaced is the volume of fluid displaced, and g is gravity. Therefore, the buoyant force is inherently tied to how much fluid is moved aside—the weight of that displaced fluid—not simply the body’s own weight, the displaced fluid’s volume by itself, or just density and gravity without the volume factor. For floating or sinking behavior, the interaction is about whether this buoyant force (the weight of displaced water) matches the object’s weight; if the displaced-water weight is greater, the object rises, if smaller, it sinks.