I have worked this problem with three sets of data and keep coming up with incorrect answers according to the online homework gizmo for my physics class. Am I wrong, or is it? The only reason I ask is it has been wrong in the past. Here is the problem as I worked it last, as well as my answers:

I used mesh, assuming both loops to travel in a clockwise direction, i1 on the left, i2 on the right. My equations are:
8.04(i1)-4.02(i2)=13.3
-4.02(i1)+8.04(i2)=-.504

I have i2 as the answer for part a, and the difference between i1 and i2 as the answer for part b.

 

Looking at the circuit there is two batteries that is adding each other.Therefore
the current is traveling in the same direction thru the center resistor.It seems to me that the total current should pass thru the center resistor and divide to the appropriate battery pull acrooss each resistor???

 

Looking at the circuit there is two batteries that is adding each other.Therefore
the current is traveling in the same direction thru the center resistor.It seems to me that the total current should pass thru the center resistor and divide to the appropriate battery pull acrooss each resistor???

Not in this case. If the voltage sources were precisely matched that would be true though. Think of the alternator in your car. If it applies 14 volts to the positive terminal of the 12.6 volt battery, is the battery still a source, or has it become a load?

 

Your solution is the same one I come up with.

 

Your solution is the same one I come up with.

Thanks for the varification. Like I said, its not the first time I have had problems with this application. Unfortunately, I have also made many erroneous calculations myself, and this sort of thing does not instill confidence. Thanks again.

 

I don't know why, but most of our books are riddled with errors also.