A projectile with a mass of m, flying at a velocity \(v_0\), penetrates a wall with a thickness of 3h. The wall offers resistance \(R = v^2 + 8v\). Neglecting the influence of gravity on the projectile, calculate the velocity \(v_1\) that the projectile will have after penetrating the wall. How thick would the wall have to be for the projectile to get stuck in it?