Question

. A piece of gold is suspended from a string and then completely immersed in a container of mercury. The volume of gold is 300cm3 and its density is 19.3 X 103 kg/m3 . Calculate the tension in the string before and after the gold is immersed in mercury.

Answer 1

The tension in the string before the gold is immersed in mercury

$T=mg=\rho Vg=19300\cdot300\cdot10^{-6}\cdot9.8=56.742\ (N)$

The tension in the string after the gold is immersed in mercury

$T=\rho_{Au} Vg-\rho_{Hg}Vg=19300\cdot300\cdot10^{-6}\cdot9.8-$

$-13520\cdot300\cdot10^{-6}\cdot9.8=17\ (N)$