22. The switch above the 12 V source in the circuit of Fig. 8.60 has been closed

since just after the wheel was invented. It is finally thrown open at z = 0.

(a) Compute the circuit time constant. (b) Obtain an expression for v(1) valid

for t > 0. (c) Calculate the energy stored in the capacitor 170ms after the

switch is opened.

20k12

w

:5 μF

12 V

IFIGURE 8.60

3 k0

10k2

5kQ

1kQ