$${v = \sqrt{\frac{8 k T}{\pi m}} = \sqrt{\frac{8 \times 1,38 \times 10^{-23} \times 295}{3,14\times 4,7\times 10^{-26}}} = 470 \mathrm{m/s}~~~~ \mathrm{or} ~~~~ v = \sqrt{\frac{8 RT}{\pi M}}.}$$