Demonstration of Buoyant Force
An object that is partly or completely submerged experiences a higher pressure on the bottom surface than on its top surface. This force is called upthrust. When we put something on the water body’s surface, it displaces some of the fluid. The upthrust force is equal to the weight of the fluid displaced by the object.
A floating object is stable if it tends to restore itself to an equilibrium position after a small displacement. For example, floating objects will generally have vertical stability. As if the object is pushed down slightly, this will create a greater buoyancy force, which, unbalanced by the weight force, will push the object back up. Given a small angular displacement, the vessel may return to its original position (stable), move away from its original position (unstable), Or remain where it is (neutral). Rotational stability depends on the relative lines of action of forces on an object. The upward buoyancy force on an object acts through the center of buoyancy (CB), being the centroid of the displaced volume of fluid. The weight force on the object acts through its center of gravity (CG).
The buoyant object will be stable if the center of gravity is beneath the center of buoyancy because any angular displacement will then produce a ‘righting moment’. The stability of a buoyant object at the surface is more complex, and it may remain stable even if the center of gravity is above the center of buoyancy, provided that when disturbed from the equilibrium position, the center of buoyancy moves further to the same side that the center of gravity moves, thus providing a positive righting moment.
What is Upthrust?
Any object placed in a fluid receives an upward force called Upthrust. The object is pushed in an upward direction, therefore, named Upthrust. An upthrust is a force that is applied by the water, and one other force is also acting on the body due to the mass of the body which is known as gravitational force. Gravitational force is acting in the opposite direction of upthrust force, Upthrust force acts in the vertically upward direction, and the Gravitational force acts in the vertically downward direction. The unit of upthrust is Newton.
Buoyant Force
Buoyancy is a phenomenon due to the buoyant force that causes an object to float. When you put an object in a liquid, an upward force is exerted on the object by the liquid. This force is equal to the weight of the liquid that has been displaced. The amount of liquid that has been displaced depends upon the density and the volume of the object immersed in the liquid. Have you ever wondered why an iron nail sinks in water, but a ship made up of iron floats? And why does an iron ball sink but a plastic ball of the same size floats in water? These wonders happen due to the phenomenon known as Buoyancy. Let’s learn the buoyancy definition, buoyancy equation, and its examples in detail.
Table of Content
- What is Buoyant Force?
- What causes Buoyant Force?
- Archimedes’ Principle
- Formula for Archimedes’ Principle
- Derivation of the Formula
- Demonstration of Buoyant Force
- Why does an Object float or sink in the water?
- Types of Buoyancy
- Applications of Buoyancy
- Solved Examples on Buoyancy