A mass m $=0\mathrm{.}10$ kg is suspended by a vertical spring of stiffness k $=3\mathrm{.}0$ N$/$m with negligible damping.At t $=0$ the mass is $0\mathrm{.}12$ m below its equilibrium position and moving upward at $0\mathrm{.}5$ m$/$s$.($a$)$ Using these initial conditions, find an expression for y$($t$),$ the position of the mass as a function oftime $.($b$)$ Find the first time t $>0$ at which the mass reaches its maximum height.