There is kinetic energy when it is sitting at the top, then as it goes towards the bottom, the kinetic energy is transformed into potential energy.
5 minutes is the minimum time
Answer:
200 N/m
20 rad/s
0.31415 seconds
3.18309 Hz
Explanation:
m = Mass of glider = 0.5 kg
x = Displacement of spring
F = Force on spring = 6 N
From Hooke's law we have relation

The spring constant is 200 N/m
Angular frequency is given by

The angular frequency is 20 rad/s
Frequency is given by

The frequency is 3.18309 Hz
Time period is given by

The time period is 0.31415 seconds
It will not explode since the mass of the cotton balls is so low but rather will most likely break the lock and hinges and come out.