A person travelling on a straight line moves with a uniform velocity ${v_1}$ for a distance x and with a uniform velocity ${v_2}$ for the next $\frac{3}{2}x$ distance. The average velocity in this motion is $\frac{{50}}{7}m/s$. If ${v_1}$ is $5m/s$ then ${v_2}=$ ______ m/s.