The block of mass m is attached to a frame by spring of force constant k, entire system moves horizontally without any frictions anywhere. The frame and block are at rest with x = x0, the relaxed length of spring. If frame is given a constant acceleration a0. Determine the maximum velocity of block relative to frame (in m/s). (Given: a0 = 2 m/s2, m = 4 kg, k = 4 N/m)