Use Kirchoff's laws to solve for tension and current

[Cocoleia]

Homework Statement

http://postimg.org/image/ys43ylstp/ [/B]
I need to find tension and current in each element of the circuit. I have included an image of what I have drawn so far for the circuit. http://postimg.org/image/ys43ylstp/

Homework Equations

Kirchoff's laws.

The Attempt at a Solution

I separated it into three loops. The one on the top I called loop 1 and the equation would be:
-5+R2I2+R1I1=0
loop 2 is the one underneath:
15+R3I3-R2I2=0
and loop 3 is on the far left:
-15+5+R4I4=0
Are these the right equations? Whenever I try to use the node law I always mix up something. Can someone please help me solve this problem?

 

[cnh1995]

It is better to insert image in the OP itself than posting its link.

I separated it into three loops. The one on the top I called loop 1 and the equation would be:
-5+R2I2+R1I1=0
loop 2 is the one underneath:
15+R3I3-R2I2=0
and loop 3 is on the far left:
-15+5+R4I4=0

Observe the circuit carefully. You can get all the currents(and voltages) just by inspection and not a single equation is required.

 

[Cocoleia]

View attachment 106508
It is better to insert image in the OP itself than posting its link.

Observe the circuit carefully. You can get all the currents(and voltages) just by inspection and not a single equation is required.

Sorry about the picture.

I have been working on it, and I assume that the current going through R1 would be 1.5A and the current going through R3 would be 0.5A.
I am also thinking that I2 = 1.5-0.5, which will let me calculate the tension for R2.
Could I combine the 2 voltage sources, as if they were in series, and get a single voltage source of 20V? Then that would be the voltage of R4 and I could calculate the current?

 

[gneill]

Could I combine the 2 voltage sources, as if they were in series, and get a single voltage source of 20V? Then that would be the voltage of R4 and I could calculate the current?

Yes you can sum their potentials in series, however, beware of the polarities of the voltage sources!

You seem to be doing fine applying KCL where required and filling in the potential drops across the resistors. Keep going!