# Magnetic Forces with Currents

1. Oct 17, 2011

### blackbyron

1. The problem statement, all variables and given/known data
A wire of length 95m and a diameter of 2.4mm has a total resistance 1.59Ohms. The potential difference between the ends of the wire is 103volts. A section of the wire 15.5cm in length is bent into an arc of 60deg. The magnetic field is parallel to the bisector of the arc and has a strength of B=1.4T . What is the magnitude of the magnetic force on the arc of wire?

2. Relevant equations
F = I*l*B*sin(Phi)

3. The attempt at a solution

I found the current by solving I = V/R which gives me 64.78 Amps.

Now the part I'm having trouble with is finding out the magnetic field that is parallel to the bisector of the arc. I don't think I understand this question The magnetic field is parallel to the bisector of the arc and has a strength of B=1.4T .

What are your suggestion on this one? And fyi, my teacher didn't lecture this topic yet, but the reason I want to do HW early is to have more time to study this so I can get good grade on the next test.

2. Oct 19, 2011

### blackbyron

bump I got the current, and the length. I'm still having trouble with finding the right B*sin(phi).