$19-64.$ A $5$ kg uniform rod CD of length $\backslash ($ l$=0\mathrm{.}75\backslash$mathrm$\{$~m$\}\backslash )$ is welded at $\backslash ($ C $\backslash )$ to two elastic rods, which have fixed ends at $\backslash ($ A $\backslash )$ and $\backslash ($ B $\backslash )$ and are known to have a combined torsional spring constant $\backslash ($ K$=30\backslash$mathrm$\{$Nm$\}/\backslash$mathrm$\{$rad$\}\backslash ).$ Determine the period of small oscillation if the equilibrium position of CD is $($a$)$ vertical as shown, $($b$)$ horizontal.