The mass of weight 32 lb(mass m = 1 slug) is attached to the free end of long light spring which is stretched 1 ft by the force of 4 lb(k = 4lb/ft). Mass is initially at rest in equilibrium position. Starting at time t = 0(sec), the external force F(t) = cost is applied to mass, but at time t = 2 this force is turned o (abruptly discontinued) and mass is permitted to continue motion unimpeded. Determine resulting position u(t) of mass at any time and draw its graph.