Buoyancy is the upward force exerted by a fluid on a submerged object, opposing its weight. What is this force called?

• A. Buoyancy
• B. Gravity
• C. Drag
• D. Pressure

Answer: (A)

Buoyant force is the upward push that a fluid applies to any object immersed in it. It arises because fluid pressure increases with depth, so the pressure beneath the object is greater than the pressure above it, creating a net upward force that opposes the object's weight. According to Archimedes’ principle, this buoyant force equals the weight of the fluid displaced by the object. If the buoyant force exceeds the object's weight, the object rises; if it’s smaller, the object sinks. Gravity is the downward pull on the object’s mass, drag is resistance to motion through the fluid, and pressure is the local force per area from the fluid—none of these alone is the net upward support produced by the fluid.