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Electromagnetic Induction

  1. May 29, 2010 #1
    I have one question about the eddy current brake, or electromagnetic induction at all. For instance, slowing a roller coaster from let me say 40m/s to 10m/s in 20m by a eddy current brake(THIS IS NO HOMEWORK!). What is about the conservation of energy in this case. can you say that E kin + Epot->E' kin + E' pot + E' therm or is this wrong? Is it valid to use the conservation of energy in this case at all? I am not sure! How do you think about this problem? I am not even sure, whether all the energy lost by the slowing down procedure goes into thermal energy?

    sry about my english, but I do not live in a english-speaking country...:smile:
  2. jcsd
  3. May 29, 2010 #2
    The kinetic energy is turned into heat.
  4. May 30, 2010 #3
    So you would say that the kinetic energy of the roller coaster at the beginning is turned into heat and the potential energy is turned into kinetic energy, electric potential energy and the potential energy at the end?

    I just want to be sure that I understand you right!
    Last edited: May 30, 2010
  5. May 30, 2010 #4
    or can somebody explain me more precisely which kinetic energy is transformed into heat. the initial kinetic energy or also energy of the brake procedure?
  6. May 31, 2010 #5
    can nobody help me with my problem? :frown:
  7. May 31, 2010 #6
    Eddy Currents are generated when something conducting moves in a Magnetic field. The brake converts the rotational energy of the wheels into eddy currents and these currents are dissipated because of electrical resistances in the conductor.
    The kinetic energy deceases because of friction between the wheel and the track.If the brakes are sufficiently weak rolling will be maintained else the system will try to slide.
    The kinetic and rotational energy lost will be equal to the heat lost from eddy current and friction.
  8. May 31, 2010 #7
    okay thanks a lot, so if there is no friction then all energy is turned into heat. does this mean that antiphon was wrong, when he said that just kinetic energy is turned into heat or what happens to the potential energy, since I was talking about a roller coaster, which has also potential energy?
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