Can someone help to solve this problems please?

Exercise 1. Undamped free motion

1.A spring hangs vertically; Its top end is fixed, and a box weighing 150 lb hangs from the bottom end. Once in equilibrium, the box is pulled downwards, making it move 1/2ft and released. Knowing that k=50 lb/ft and that air resistance is negligible, find the equation of motion of the box.

Exercise 2. Damped free motion

2. A body that weighs 20N stretches a spring 2cm. Considering that a retarding force equal to 3 times the instantaneous velocity acts on the system and that the weight is released 5 cm below the equilibrium position with an upward velocity of 10 m/s, determine the equation of motion.