Question

The apparent weight of a floating body is

& A.2 \\\ & B.0 \\\ & C.5 \\\ & D.8 \\\ \end{aligned}$$

Answer 1

We know that the weight of a body is the attractive force exerted by the gravity on the body. Similarly, apparent weight is the vector sum of the weight of an accelerating body and the sum of all the negative forces acting on the body.

Formula used:
$w_{app}=w_{real}-F$

Complete answer:
We know that apparent weight occurs when the force due to gravity on an object is unbalanced by its opposite normal force. This concept of apparent weight also leads to weightlessness of any body.
Let a body of mass $m$ be immersed in a liquid, here water. Then the weight of the body is given as $W=mg$
Let $V$ be the volume of the body immersed in the water. Then the buoyant force $B$ acting on the body is given as $B=\rho gV$ where $\rho$ is the density of the liquid, here it is water.
For a body to float, the buoyant force must be equal to the weight of the body. Or $B=W$
We know that the apparent weight of the a body is given as $w_{app}=w_{real}-F$
Here, $w_{app}$ is the apparent weight , $w_{real}=W$ is the real weight and the net opposing force is $F=B$.
Then, we can say that $w_{app}=W-B$
Since $B=W$
Then, $w_{app}=0$
Thus, the apparent weight of a floating body is $0$

So, the correct answer is “Option B”.

Note:
The normal force is equal and opposite to the force due to gravitation. Here, we are using three terms namely mass, weight and apparent weight, which might seem similar. But they are different and defined as follows:
1. Mass: it is a property of a body to resist the change in its motion.
2. Weight: it is the force of gravitation acting on a body.
3. Apparent weight: The difference in the weight and the forces acting on a body.