A particle is moving along the $x$-axis with its coordinate with time ' $t$ ' given by $x(t)=10+8 t-3 t^2$. Another particle is moving along the $y$-axis with its coordinate as a function of time given by $y(t)=5-8 t^3$. At $t=1 \mathrm{~s}$, the speed of the second particle as measured in the frame of the first particle is given as $\sqrt{v}$. Then $v($ in $\mathrm{m} / \mathrm{s})$ is $\_\_\_\_$ .