# What is the magnitude of the force the first exerts on the second?

1. Jul 4, 2009

### mba444

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

A circular loop of wire of radius R = 3.67 m
lies in the xy-plane, centered about the origin.
The loop is carrying a current of I = 6.2 A
flowing in counterclockwise direction.

Consider two l = 1.63 mm segments of the
loop: one centered about the positive x-axis,
the other centered about the positive y-axis.
Hint: Use Biot-Savart law.
The permeability of free space is
1.25664 × 10−6 Tm/A

What is the magnitude of the force the first
exerts on the second? Answer in units of N.

2. Relevant equations

dB = Uo*i*ds×r/(4*pi*r^2)

3. The attempt at a solution

i didnt understand the problem well, as a result i couldnt figure out how to solve it

i am seeking for your help

2. Jul 5, 2009

### rl.bhat

Field at the point on the y-axis due to the current element on the x-axis is
dB = μο/4π*i*ds*sinθ/r^2. Here θ is 45 degrees. Direction of the field is perpendicular to the current element on the y-axis. Hence the force on the current element is
df = dB*i*ds.