Question

An irregular piece of metal weighs $10.00g$ in air and $8.00g$ when submerged in water. If the same piece of metal weighs $850g$ when immersed in a particular oil, what is the density of the oil ?

Answer 1

Change in weight = upthrust on 100% volume of solid

or $\Delta W=V_s{\rho }_{l}g$

$\therefore$ $\Delta W\propto {\rho }_l$

$\therefore$ $\frac{\Delta W_l}{\Delta W_w}=\frac{{\rho }_l}{{\rho }_w}$
${\rho }_l=\left(\frac{\Delta W_l}{\Delta W_w}\right){\rho }_w=\left(\frac{1.5}{2}\right)\left(1000\right)$

$=750kg/m^3$