Question 147 of 308

A particle is moving along the $x$ -axis with its coordinate with time $t$ given by $x\left(t\right)=10+8t-3{t}^{2}.$ Another particle is moving along the $y$ -axis with its coordinate as a function of time given by $y\left(t\right)=5-8{t}^{3}.$ At $t=1s,$ the speed of the second particle as measured in the frame of the first particle is given as $\sqrt{v}.$ Then $v\left(inm{s}^{-1}\right)$ is ___________.