A block of mass $m=8,7kg$ slides on a rough surface and moves toward a spring with a spring constant $k=1680\frac{N}{m},$ as shown in the figure below. When the block is $d=18,8m$ away from the spring, it has a velocity of $v.$ At the instant the block momentarily stops, it has compressed the spring by $x=15cm.$ If the coefficient of kinetic friction between the block and the surface below is ${}_k=0,33,$ what is the block's velocity, $v=?$ Provide your answer in units of $\frac{m}{s}$ using one decimal place. Take $g=0\mathrm{.}80\frac{m}{s^2}.$