Answer:
M g H = 1/2 M v^2 + 1/2 K x^2
H = 1 + .2 = 1.2 m Left side is original potential energy that is converted to kinetic energy and potential energy (H given as 1.2 m)
v^2 = 2 g H - K x^2 / M
v^2 = 2 * 9.8 * 1.2 - 490 * .04 / 4 = 23.5 - 4.9 = 18.6 m^2 / s^2
v = 4.31 m/s