Current Articles | Archives Buoyant Forces and Archimedes' PrincipleStaff posted on November 10, 2006 | Buoyant Forces and Archimedes' Principle Archimedes' principle can be stated as follows: Any body completely or partially submerged in a fluid is buoyed up by a force equal to the weight of the fluid displaced by the body. Everyone has experienced Archimedes' principle. As an example of a common experience, recall that it is relatively easy to lift someone if the person is in a swimming pool whereas lifting that same individual on dry land is much harder. Evidently, water provides partial support to any object placed in it. The upward force that the fluid exerts on an object submerged in it is called the buoyant force. According to the Archimedes' principle, The magnitude of the buoyant force always equals the weight of the fluid displaced by the object. The buoyant force acts vertically upward through what was the center of gravity of the displaced fluid. B = W Where B is the buoyant force and W is the weight of the displaced fluid. The units of the buoyant force and weight are newton ( N ) in SI and "pound force" ( lbf) in British Engineering units. The buoyant force acting on the steel is the same as the buoyant force acting on a cube of fluid of the same dimensions. This result applies for a submerged object of any shape, size, or density. Please enable JavaScript to view the comments powered by Disqus.