The characteristics of a horizontal and undamped spring-block system are k=400N/m and M=0.3kg.The position of the block is determined by its abscissa along an x'ox axis. When the spring has its natural length then x=0.

a) the spring is stretched by shifting the block by 10 cm from its equilibrium position and then releasing it at to=0.
determine the time equation of motion.
b) the spring is compressed by shifting the block by 10cm from its equilibrium position and then releasing it at to=0.
determine the time equation of motion.