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posted by  goldgirlscout3604 on 4/21/2008 2:24:54 PM  |  status: Live  

physics help fast!!!!!! I will rate you the highest if you solve this problem for me guaranteed!!!!!!!!!!!

Course Textbook Chapter Problem
Calculus Based Physics University Physics with Modern Physics (12th) by Young, Freedman N/A N/A
Question Details:
Evaluate the currents I1, I2, and I3 in the following circuit:

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posted by Michaelh on 4/21/2008 2:39:01 PM  |  status: Live
Asker's Rating: Lifesaver   
goldgirlscout3604's comment:
"thank you so much!!!!!"
Response Details:
You can do this using loop analysis:
 
Let the current in the upper loop be I1.
Let the current in the lower loop be I2.
 
Taking the loop on the top:
 
20 + 5I1 + 10 + 10(I1 - I2) = 0      =>      15I1 - 10I2 = -30 ........... (1)
 
Taking the loop on the bottom:
 
20I2 + 10(I2 - I1) - 10 + 10I2 + 30 = 0      =>   -10I1 + 40I2 = -20 ......... (2)
 
Solving (1) and (2):
 
I1 = -2.8 A      I2 = -1.2 A
So, I1 you are asking for is simply I1 = -2.8 A
 
I2 you are asking for is I2 = -1.2 A
 
I3 = I2 - I1 = 1.6A
Michael
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