# Help with electricity, four wires that carry current

1. Mar 9, 2014

1. The problem statement, all variables and given/known data
So four wires are arranged in a square and all carry the same current "I"
They are all the same distance apart. The two on the left are coming out towards you "O" and the two on the right go away from you "X"

I knew I would need k$I^{2}$ divided by distance, but I"m not sure how to find the force, per unit length on the lower left wire. I have to find the magnitude and direction.

2. Mar 9, 2014

### SammyS

Staff Emeritus
You need to show an attempt at a solution before we can help you.

3. Mar 9, 2014

:-l

I have.
I try to set it up so that I can break things into vectors in X and Y for both, but I'm not sure how to put together an answer.

4. Mar 9, 2014

### SammyS

Staff Emeritus
What is the question you are trying to answer ?

5. Mar 9, 2014

### Simon Bridge

What you have done is too vague.
Do you know the formula for the force on one current carrying wire due to another one?
Did you try working out the force due to each of the other three wires separately, then summing the vectors?
This is like the square of point charges problems you have done before only with magnetism.

6. Mar 9, 2014

Okay.
Well that should be (k I^2)/distance right?
I'll try that.

7. Mar 9, 2014