Problem $18\mathrm{.}092-$ RC circuit $-$ DEPENDENT MULTI$-$PART PROBLEM $-$ ASSIGN ALL PARTS

In the circuit, at $t=0$ the switch is closed.

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Problem $18\mathrm{.}092.$b $-$ Time at which the capacitor has a particular energy

In the circuit, the initial energy stored in the capacitor is $56\mathrm{.}1$ J $.$ At what time is the energy stored in the capacitor $1\mathrm{.}25$ J $?$

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