Two blocks of masses 3 kg and 5 kg are connected by a metal wire going over a smooth pulley. The breaking stress of the metal is $\frac{24}{\pi} \times 10^2 \mathrm{Nm}^{-2}$. What is the minimum radius of the wire?
$\left(\right.$ Take $\left.\mathrm{g}=10 \mathrm{~ms}^{-2}\right)$
