A mass $m$ is attached to a spring which is held stretched a distance $x$ by a force F, Fig. 6-45, and then released. The spring pulls the mass to the left, towards its natural equilibrium length. Assuming there is no friction, determine the speed of the mass m when the spring returns: (a) to its normal length ($x =$ 0); (b) to half its original extension($x$/2). FIGURE 6-45(Figure Cant copy)