A spring bumper, whose force-compression relationship is given by F = 50 x, is compressed 0.20 m.

        (a)    What is the potential energy stored in the spring at a compression of 0.20 m?
        (b)    The spring is compressed further to 0.60 m.  What will be the change in elastic potential energy?
        (c)    A 0.40 kg cart is placed against the compressed spring on a horizontal, frictionless plane, and the system is released.
                With what velocity will the cart leave the spring?