(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

Two straight wire are suspended from the ceiling by strings length of 0.75m.

each wire has a mass of 45g and a length of 1m

When identical current flows in opposite directions, the angle between the string is 12°.

2. Relevant equations

Fg=mg

B=μI/2πR

F=LIBsin(theta)

3. The attempt at a solution

From the looks of it, I assumed that this was an equilibrium question meaning that the force of (BIL) is the same on both wires, working in opposite directions to create an angle of 12°.

I also assumed that the force of gravity (.441) is equal to the Y component of the string, so then i used trig to solve for the force of the X component which i found to be .0464.

The force of the X component is the same force as the (BIL) and in order for the forces to be the same, the magnetic field and current has to be the same.

so then i combined B=μI/2πR with F=LIBsin(theta) in order to cancel out the magnetic Field since it did not matter.

I got F= LμI^{2}/2πR

I figured out the current to be 131.9

I would attach a picture of my work but i don't have 10 post..

imageshack.us/photo/my-images/265/photo20120607121104pm.jpg/

1. The problem statement, all variables and given/known data

2. Relevant equations

3. The attempt at a solution

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# Homework Help: Magnetic Fields and Forces

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