A spring of unstretched length l has a mass m with one end fixed to a rigid support .Assuming spring to be made of a uniform wire , the kinetic energy possessed by it if its free end is pulled with uniform velocity v is :

Question

$(a)\;\large\frac{1}{2}mv^{2} \qquad(b)\;mv^{2} \qquad(c)\;\large\frac{1}{3}mv^{2} \qquad(d)\;\large\frac{1}{6}mv^{2}$