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Homework Help: Conducting slidewire see system-Faraday's Law

  1. May 5, 2015 #1
    1. The problem statement, all variables and given/known data

    A conducting slidewire system is set up as shown. The sliding wire has mass m and electrical resistance R and falls under gravity as shown. The fixed wire loop has zero resistance and lies perpendicular to a uniform magnetic field B shown pointing into the page.
    i) Use Faraday's Law to determine the maximum velocity of the slidewire.
    ii) How much power is dissipated at the peak velocity?

    2. Relevant equations


    3. The attempt at a solution
    I defined the area vector as pointing in the same direction as the magnetic field, so
    In time dt the slidewire moves a distance vdt, giving ɛ=-BLv where L is the width of the slidewire.
    I think I am simplifying the problem too much by simply rearranging for v in this equation and obtaining
    v=-ɛ/BL -should I differentiate in order to maximise v? I feel I am missing something by not including the given mass m.

    For the second part, overall current I=|ɛ|/R, so I=BLv/R


    Thanks in advance for any help, much appreciated.

    Attached Files:

  2. jcsd
  3. May 5, 2015 #2


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    But with v=-ɛ/BL you haven't determined v yet, have you !?

    Is there something that stops you from answering e.g. ## v = -{\tfrac 1 2} g t^2 ## ?

    Not so certain my help has helped. Can you enlighten me ?
    Last edited: May 6, 2015
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