Question

A body of volume 100 c$m^3$ weighs 5 kg in air. It is completely immersed in a liquid of density 1.8 x ${10}^3$ kg/$m^3$. Find the apparent weight of the body in the liquid.

• A. 4.82 kgf
• B. 5 kgf
• C. 18 kgf
• D. 5.82 kgf

Answer 1

The correct option is A 4.82 kgf

Given,
Volume, V = 100 c$m^3$ = 100 x ${10}^{-6}$ $m^3$
Weight, W = 5 kgf
Density of liquid, ⍴ = 1.8 x ${10}^3$ kg/$m^3$

We know,
upthrust, U = V x ⍴ x g
Therefore,
U = 100 x ${10}^{-6}$ x 1.8 x ${10}^3$ x g
Or, U = 0.18 g = 0.18 kgf

Apparent weight = Normal weight - Upthrust
Therefore,
apparent weight = W - U
= 5 - 0.18 = 4.82 kgf