A $18\mathrm{.}4$ kg object on a horizontal frictionless surface is attached to a spring with k $=878$ N$/$m$.$ The object is displaced from equilibrium$55\mathrm{.}3$ cm horizontally and given an initial velocity of $9\mathrm{.}14$ m$/$s back toward the equilibrium position. What are $($a$)$ the motion's frequency,$($b$)$ the initial potential energy of the block$-$spring system, $($c$)$ the initial kinetic energy, and $($d$)$ the motion's amplitude?