Question

32. A cubical block of wood of specific gravity 0.5 and
chunk of concrete of specific gravity 2.5 are fastened
together. The ratio of mass of concrete to the mass of
wood which makes the combination to float with its
entire volume submerged in water is
(b)
wolf
no
5​

Answer 1

The ratio of mass of concrete to the mass of  wood which makes the combination to float with its  entire volume submerged in water is 5 : 3

Explanation:

As we know that the two blocks are tied together such that the blocks are floating together

now we will have

$F_b = \rho V g$

Now in order to float in water the weight of two blocks must be equal to the net buoyancy force on two blocks

$m_1g + m_2g = \rho V g$

$2.5 V_1g + 0.5 V_2 g = (V_1 + V_2)1 g$

$2.5 V_1 + 0.5 V_2 = V_1 + V_2$

$1.5 V_1 = 0.5 V_2$

$3V_1 = V_2$

now ratio of masses of two blocks is given as

$\frac{m_1}{m_2} = \frac{\rho_1V_1}{\rho_2V_2}$

$\frac{m_1}{m_2} = \frac{2.5V_1}{0.5V_2}$

$\frac{m_1}{m_2} = 5 \times \frac{1}{3}$

$\frac{m_1}{m_2} = \frac{5}{3}$

#Learn

Topic : Buoyancy Force

https://brainly.in/question/7483537

Answer 2

w = upthrust

(m1 + m2 )g = [ (m1/0.5)*Pw + (m2 / 2.5)*Pw]Pwg

m1 + m2 = 2m1 + 0.4m2

m1 = 0.6 m2

m1/m2 = 0.6

i.e.

$\frac{3}{5}$