A $4\mathrm{.}30$ kg object on a horizontal frictionless surface is attached to a spring with spring constant $1150$ N$/$m$.$ The object is displaced from equilibrium $50\mathrm{.}0$ cm horizontally and given an initial velocity of $10\mathrm{.}1$ m$/$s back toward the equilibrium position.

$($a$)$ What is the frequency of the motion?

$($b$)$ What is the initial potential energy of the block$$spring system?