Step-by-step explanation:
We have,
Spring constant of the spring, k = 165 N/m
Mass, m = 2 kg
It is required to find the period of the mass-spring system. For the spring mass system, the period is given by :

The frequency of vibration is reciprocal of its time period. So,

So, the period of the mass-spring system is 0.69 s and frequency is 1.44 Hz.