An 11 kg collar is constrained to travel along a rectilinear and frictionless bar of length L = 2m that lies in the vertical plane. The springs attached to the collar are identical, and they are unstretched when the collar is at B. Treating the collar as a particle, neglecting air resistance, and knowing that at A the collar is moving upward with a speed of 23m/s, determine the spring constant k so that the collar reaches D with zero speed. Points E and F are fixed.