A 20 kg block slides along the rough surface for which the coefficient of kinetic friction is 0.2. The block strikes a nonlinear spring with a speed of v=4.5 m/s. The spring is termed "nonlinear" because it has resistance of Fs=ks^2 where k = 900 N/m^2. Determine the speed of the block after it has compressed the spring s=0.2m?