Be Careful with Liquid

A rectangular tank having base $\SI{15}{\centi\meter} \times \SI{20}{\centi\meter}$ is filled with water (density $\rho = \SI[per-mode=symbol]{1000}{\kilo\gram\per\meter\cubed}$ ) up to $\SI{20}{\centi\meter}$ height. One end of an ideal spring of natural length $h_0 = \SI{20}{\centi\meter}$ and force constant $K = \SI[per-mode=symbol]{280}{\newton\per\meter}$ is fixed to the bottom of the tank so that the spring remains vertical. This system is in an elevator moving downwards with acceleration $a = \SI[per-mode=symbol]{2}{\meter\per\second\squared}$ . A cubical block of side $l = \SI{10}{\centi\meter}$ and mass $m = \SI{2}{\kilo\gram}$ is gently placed over the spring and released gradually.

1. Find the compression $a$ (in $\si{\centi\meter}$ ) in the spring in the equilibrium position.
2. If the block is slightly pushed down from the equilibrium position and released, find the frequency of oscillation about the equilibrium position $f = \dfrac {b\sqrt c}\pi$ (in $\si{\hertz}$ ), where $b$ and $c$ are positive integers with $c$ being square-free.

Enter your answer as $abc$ .

This is a part of my set Aniket's Mechanics Challenges .