Capacitors homework help

1. Feb 5, 2006

villampaxo

any ideas on solving this? (the capacitors are initially charged) I have some ideas but im not sure which one is correct... I know that Q remains the same between C1 and C2, so that V1C1 + V2C2 = v1'C1 + V2'C2. From there, i dont know if i can do the same thing for capacitors C2 and C3. I can use Kirchoff for the whole circuit... Is the total charge before and after the switch is closed maintened so that i can use: V1C1 + V2C2 + V3C3= v1'C1 + V2'C2 + V3'C2 ??? (Vx' after the switch is closed, Vx before)

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Last edited: Feb 5, 2006
2. Feb 5, 2006

villampaxo

Id appreciate a quick reply cause I have exams coming up...

3. Feb 6, 2006

brasilr9

The net charge of the whole circuit seems to be zero. So i'm not sure that whether you can you use it or not. But I don't have any idea either.

Last edited: Feb 6, 2006
4. Feb 6, 2006

villampaxo

I think the answer is: that the charge between C1 and C2 is the same before and after the switch is closed, and the total charge of the circuit remains the same so: C1V1 + C2V2= C1V'1+ C2V'2 and also, the total charge of the circuit remains the same so you ve got two equations. I think that kirchoff can be used too.