let R $57\mathrm{.}60$ V$,$ L $52\mathrm{.}20$ mH$,$ and C $5$

$1\mathrm{.}80$ mF$.($a$)$ Calculate the frequency of the damped oscilla$-$

tion of the circuit when the switch is thrown to position b$.$

$($b$)$ What is the critical resistance for damped oscillations?