Fluid Mechanics Viscosity Question 196

Question: Two solids A and Bfloat in water. It is observed that A floats with $ \frac{1}{2} $ of its body immersed in water and B floats with $ \frac{1}{4} $ of its volume above the water level. The ratio of the density of A to that of B is

Options:

A)4 : 3

B)2 : 3

C)3 : 4

D)1 : 2

Show Answer

Answer:

Correct Answer: B

Solution:

Upthrust = weight of body For A, $ \frac{V_{A}}{2}\times {\rho_{W}}\times g=V_{A}\times {\rho_{A}}\times g\Rightarrow {\rho_{A}}=\frac{{\rho_{W}}}{2} $ For B, $ \frac{3}{4}V_{B}\times {\rho_{W}}\times g=V_{B}\times {\rho_{B}}\times g\Rightarrow {\rho_{B}}=\frac{3}{4}{\rho_{W}} $ (Since 1/4 of volume of B is above the water surface) \ $ \frac{{\rho_{A}}}{{\rho_{B}}}=\frac{{\rho_{W}}/2}{3/4\ {\rho_{W}}}=\frac{2}{3} $