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1. Homework Statement What is the magnitude and direction of the current in the following circuit?
[URL=http://imageshack.us][PLAIN]http://img234.imageshack.us/img234/7587/circuituk2.gif[/URL][/PLAIN]
resistance for series: Req=R1+R2+R3+R4....etc
Kirchhoff's rules > Loop Rule: sum of potential drops must equal sum of potential rises
V=IR
3. The Attempt at a Solution
1st added all the voltage drops: I(5+27+12+8) = I52
2nd added all the Voltage rises: 30 + 10 = 40V
3rd solved for V when V=IR
40 volts/52 ohms= I
*since resistors are in series they experience the same current right?
my answer .77 Amps clockwise [which is wrong] the right answer is .38 Amps clockwise
My question is this: Why am i not supposed to add the voltages (30+10) together when solving this problem?? If i solve for this problem in the following way, 30V10V = I(52ohms) then i get .38 Amps clockwise (which is right) but i don't understand why i have to subtract the voltages!
[URL=http://imageshack.us][PLAIN]http://img234.imageshack.us/img234/7587/circuituk2.gif[/URL][/PLAIN]
resistance for series: Req=R1+R2+R3+R4....etc
Kirchhoff's rules > Loop Rule: sum of potential drops must equal sum of potential rises
V=IR
3. The Attempt at a Solution
1st added all the voltage drops: I(5+27+12+8) = I52
2nd added all the Voltage rises: 30 + 10 = 40V
3rd solved for V when V=IR
40 volts/52 ohms= I
*since resistors are in series they experience the same current right?
my answer .77 Amps clockwise [which is wrong] the right answer is .38 Amps clockwise
My question is this: Why am i not supposed to add the voltages (30+10) together when solving this problem?? If i solve for this problem in the following way, 30V10V = I(52ohms) then i get .38 Amps clockwise (which is right) but i don't understand why i have to subtract the voltages!
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