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Magnitude in a rectangular loop

  1. Dec 14, 2006 #1
    1. The problem statement, all variables and given/known data
    The rectangular loop has a mass of .15 g per centimeter of length and is pivoted about side ab on a frictionless axis. The current in the wire is 8.2 A in the direction shown. Find the maggnitude and direction of the magnetic field parallel to the y-axis that will cause the loop to swing up until it's plane makes an angle of 30 degrees with the yz plane.

    2. Relevant equations

    B= Magnitude
    30 degrees
    A= area (8cm*6cm)=48cm^2 => .48m^2

    3. The attempt at a solution

    using the right hand rule i know the direction is in the + y-direction.
    with the equation i have, i don't how to fit the mass of the loop. so then i was trying to find the force but lack enough information from the problem. please help!
  2. jcsd
  3. Dec 14, 2006 #2
    side ab is on the z-axis
  4. Dec 14, 2006 #3
  5. Dec 14, 2006 #4
    side ab lies on the z axis
  6. Dec 14, 2006 #5
    how can i use mass in this problem?
  7. Dec 14, 2006 #6


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    Science Advisor
    Homework Helper

    The mass of the loop comes in as part of the gravitational force acting on the loop. While the magnetic field is responsible for the torque in one direction, gravity provides an opposing torque that keeps the loop in equilibrium.
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