Explain buoyant force and buoyancy.
Buoyancy is also known as upthrust, is an upward force exerted by a fluid that opposes the weight of an immersed object. In a column of fluid, pressure increases with depth as a result of the weight of the overlying fluid. The behavior of an object submerged in a fluid is governed by Archimedes' Principle. Archimedes determined that a body which is completely or partially submerged in fluid experiences an upward force called the Buoyant Force, B, which is equal in magnitude to the weight of the fluid displaced by the object. This principle can be used to explain why ships, loaded with millions of kilograms of cargo, are able to float.