Question

Define 'Buoyant force'. What is the cause of buoyant force? Explain an activity to show how buoyant force changes as the volume of an object immersed in water changes.

Answer 1

Hint: The upward force produced by a fluid against the weight of a partially or fully submerged item is known as buoyancy or upthrust. The weight of the overlying fluid causes pressure to rise with depth in a column of fluid. As a result, the pressure at the bottom of a fluid column is larger than at the top. In the same way, the pressure at the bottom of an item submerged in a fluid is larger than the pressure at the top.

Complete answer:
The force that enables objects to float is known as buoyancy. It's the force applied to an item that's partially or completely submerged in a liquid. The differential in pressure occurring on opposing sides of an item submerged in a static fluid causes buoyancy. The buoyant force is another name for it. The phenomenon of buoyancy is caused by the Buoyant Force. When an object is placed in or immersed in a fluid, buoyancy is defined as the upward force exerted by the fluid on the object or body.
Experiment: Assume the weight of a rock hanging by a thread in a vacuum with gravity acting on it is 10 newtons. Assume that when the rock is lowered into water, it displaces 3 newtons of water. It then produces a force of 10 newtons on the string from which it hangs, less the 3 newtons of buoyancy force: 10-3 = 7 newtons. The apparent weight of things that have sunk fully to the seafloor is reduced by buoyancy. It is usually simpler to raise an object out of the water than it is to drag it up through it.

Note:
In comparison to most solids and liquids, air has an extremely low density. As a result, an object's weight in air is nearly equal to its actual weight in a vacuum. For most items, the buoyancy of air is ignored during a measurement in air since the mistake is generally minor (typically less than 0.1 percent except for objects of very low average density such as a balloon or light foam).