# Homework Help: Biot-Savart Law

1. Feb 26, 2012

### kjlchem

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

Three infinite straight wires are fixed in place and aligned parallel to the z-axis as shown. The wire at (x,y) = (-21 cm, 0) carries current I1 = 2 A in the negative z-direction. The wire at (x,y) = (21 cm, 0) carries current I2 = 1 A in the positive z-direction. The wire at (x,y) = (0, 36.4 cm) carries current I3 = 5.8 A in the positive z-direction.

What is Fx(1), the x-component of the force exerted on a one meter length of the wire carrying current I1?

2. Relevant equations

(1) F = IL x B

(2) B= μI/2∏R

3. The attempt at a solution

I found that B of 2 on 1 is 4.76*10^-7 T and B of 3 on 1 is 5.524*10^-6 T using equation 2. I think that B (2,1) is in the negative vertical direction, and that B (3,1) is pointed 60° S of the x axis. So, to find the y components of both (the x component of the F, the only thing I need to do is multiply B (3,1) times the sine of 60 and then I can use equation 1 to give me the force. Unfortunately, this is not correct. I don't understand what I am doing wrong.

File size:
135.9 KB
Views:
283