Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Linear acceleration in a uniform magnetic field due to torque

  1. Jun 19, 2010 #1
    Here the extra credit question I'm stuck on:

    A square loop (perimeter of 4L and hinged along one side) is made of a wire that has a mass per unit length of 0.1000 kg/m and carries a current of 5.000 A. A uniform magnetic field of 10.00 mT directed perpendicular to the hinged side exists in the region. Determine the maximum linear acceleration magnitude, (a t) max , of the side of the loop opposite the hinged side.

    My Question:
    My teacher gave me a hint that torque = I*alpha, where I is the moment of inertia. How do I find the moment of inertia for this box? Then how do I work with angular acceleration to get the answer I'm after?

  2. jcsd
  3. Jun 19, 2010 #2
    What is the axis of rotation of the loop.

    To find out I of the loop about this axis, you will need to find out the I's for each side of the loop about the axis and sum them.

    [tex]\tau = I \alpha[/tex]

    [tex]a = r \alpha[/tex]

    You can see that a depends upon the torque and it is max when the torque is max.

    When is the torque max?
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook