A particle of mass m is released from rest at B and is accelerated to the left by the action of the elastic cord ABC which lies in the horizontal plane, and which is unstretched at x = 0. The cord has a unit stiffness K, which is the ratio of its tension force to its unit elongation or strain (change in length divided by original length). Determine the expression for the velocity v reached by the particle at the instant the cord returns to the straight position. Solve the problem in two ways: (a) without energy methods and (b) with energy methods