For a car moving with uniform speed along a circular track, the centripetal acceleration is provided by the frictional force acting radially inwards. Therefore, applying Newton's second law along radial direction,

$\mu mg=\frac{m{v}^2}{r}$

$\Rightarrow v=\sqrt{\mu rg}$

$=\sqrt{0.34\times 50\times 10}$

    $\approx 13 \mathrm{m} {\mathrm{s}}^{-1}$