Question

Two pieces of metals are suspended from the arms of a balance and are found to be in equilibrium when kept immersed in water. The mass of one piece is 32 g and its density 8 g $c{m}^{-3}$. The density of the other is 5 g per $c{m}^3$. Then the mass of the other is:

• A. 28 g
• B. 35 g
• C. 21 g
• D. 33.6 g

Answer 1

The correct option is B 35 g

Volume of first piece of metal = $\frac{32}{8}=4c{m}^2$
Upthrust = 4 gf
Effective weight = (32 -4) gf = 28 gf
If m be the mass of second body, volume of second body $\frac{m}{5}$
Now, 28 = $m$ - $\frac{m}{5}\Rightarrow m$ = 35 g