Capacitors Homework Help: Solving Ideas for Initial Charge and Kirchoff's Laws

AI Thread Summary
The discussion focuses on solving a capacitor circuit problem involving initial charge and Kirchhoff's laws. Participants express uncertainty about applying charge conservation principles and Kirchhoff's equations after a switch is closed. It is noted that the charge between capacitors C1 and C2 remains constant, leading to the equation V1C1 + V2C2 = v1'C1 + V2'C2. There is also consideration of whether the same approach applies to capacitors C2 and C3, with the total charge of the circuit being a key point of confusion. Overall, the consensus is that Kirchhoff's laws can be utilized to analyze the circuit effectively.
villampaxo
Messages
4
Reaction score
0
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 don`t 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)
 

Attachments

  • capac.jpg
    capac.jpg
    13.7 KB · Views: 523
Last edited:
Physics news on Phys.org
I`d appreciate a quick reply `cause I have exams coming up...
 
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:
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 kirchhoff can be used too.
 

Thread 'Errors and significant figures'

I multiplied the values first without the error limit. Got 19.38. rounded it off to 2 significant figures since the given data has 2 significant figures. So = 19. For error I used the above formula. It comes out about 1.48. Now my question is. Should I write the answer as 19±1.5 (rounding 1.48 to 2 significant figures) OR should I write it as 19±1. So in short, should the error have same number of significant figures as the mean value or should it have the same number of decimal places as...
View full post »
Thread 'A cylinder connected to a hanging mass'

Thread 'A cylinder connected to a hanging mass'

Let's declare that for the cylinder, mass = M = 10 kg Radius = R = 4 m For the wall and the floor, Friction coeff = ##\mu## = 0.5 For the hanging mass, mass = m = 11 kg First, we divide the force according to their respective plane (x and y thing, correct me if I'm wrong) and according to which, cylinder or the hanging mass, they're working on. Force on the hanging mass $$mg - T = ma$$ Force(Cylinder) on y $$N_f + f_w - Mg = 0$$ Force(Cylinder) on x $$T + f_f - N_w = Ma$$ There's also...
View full post »

Similar threads

Potential difference across capacitor in a network
Replies
8
Views
7K
Energy in capacitor at steady state
Replies
10
Views
2K
Find Charges on Capacitor w/ Floating Plates
Replies
8
Views
2K
Parallel combination of capacitors
Replies
1
Views
2K
Capacitor Charging: Voltmeter, Charge & Voltage Calculations
Replies
9
Views
2K
Capacitor in series voltage problem
Replies
19
Views
3K
How to find the charge on each capacitor
Replies
3
Views
2K
Charged Capacitor Connected to an Uncharged Capacitor in Series
Replies
9
Views
3K
Capacitors in Series and Parallel
Replies
1
Views
4K
Discharging a capacitor to to charge multiple capacitors
Replies
9
Views
2K

Hot Threads

Recent Insights

Back
Top