Question

The weight of water displaced by an iron object is $10$ kg. the buoyant force acting on the object is ?

Answer 1

Apparent loss in weight basically occurs when a body is immersed in any liquid either partially or fully. The apparent weight is a property that describes how heavy an object is.

Complete answer:
The apparent weight will differ from the actual weight of the object when the force of gravity acting on the object is not balanced by an equal and opposite force. Weight is equal to the magnitude of force of gravity that acts on an object. When an object is immersed partly or completely in any liquid then there is an apparent loss in weight due to buoyant force or upthrust exerted by that liquid in which it is immersed.

Buoyant force is that which causes objects to float. It is caused due to the differences in pressure acting on opposite sides of the object that is immersed in liquid. This phenomenon can be explained by Archimedes Principle. Archimedes principle states that the upward buoyant force that is exerted on the object immersed in a liquid whether partially or completely, is equal to the weight of the liquid displaced by the body.

Loss in weight of body$=$ Weight of liquid displaced by the body$=$ Buoyant force
Thus, due to the upward thrust exerted by the liquid, there is an apparent loss in weight of the body. So according to Archimedes principle:
Weight of liquid displaced by the body$=$ Buoyant force
$W=mg \\\ \Rightarrow W=10\times 9.8 \\\ \therefore W=98N \\\$ $(g=9.8\,m/{{s}^{2}})$
Buoyant force acting on the object is $98\,N$.

Note: The buoyant force depends on the density of fluid in which the body is immersed and volume of displaced fluid. It is caused due to the differences in pressure acting on opposite sides of the object that is immersed in liquid.