Capacitors in Series and Parallel homework

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The discussion focuses on calculating the equivalent capacitance and charge of a network of capacitors in series and parallel configurations. The given values are C1 at 7.2 µF and C2 at 4.8 µF, with a voltage of Vab set at 450 V. The user struggles to identify which capacitors are in series versus parallel, noting the rules that potential differences add in series while charges are the same in parallel. The solution involves simplifying the circuit by replacing series capacitors with their equivalent capacitance using the formula 1/C = 1/C1 + 1/C2 + 1/C3, and then addressing the parallel configuration. The conversation emphasizes understanding the arrangement of capacitors to solve the problem effectively.
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Homework Statement



In Fig. 25-22, each capacitance C1 is 7.2 µF, and each capacitance C2 is 4.8 µF

25-22.gif


(a) Compute the equivalent capacitance of the network between points a and b.

(b) Compute the charge on each of the three capacitors nearest a and b when Vab = 450 V.

(c) With 450 V across a and b, compute Vcd.


Homework Equations



Q=CV

The Attempt at a Solution



I tried figuring the total capacitance, but I can't tell what is series and what is parallel! In series I know that the potential differences add up in series and they are the same in parallel, and the opposite is true for charge. Please help!
 

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The three capacitors on the right hand end are in series.
Capacitances in series "add" according to the formula
1/C = 1/C1 + 1/C2 + 1/C3
Then you can replace the original circuit with a simpler equivilent one with the three capacitors replaced by the one.

Do it again - this time the two capacitors on the end are in parallel.
 
Okay, thank you so much!
 
The book claims the answer is that all the magnitudes are the same because "the gravitational force on the penguin is the same". I'm having trouble understanding this. I thought the buoyant force was equal to the weight of the fluid displaced. Weight depends on mass which depends on density. Therefore, due to the differing densities the buoyant force will be different in each case? Is this incorrect?

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