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Homework Help: Break-even point

  1. Apr 21, 2008 #1
    1. The problem statement, all variables and given/known data

    When discussing attempts to make any type of fusion into a workable power source, an important concept is the "break-even" point. The break-even point is reached when the fusion process generates as much energy as was initially put in (i.e., the energy output equals the energy input). The rest energy of a muon is 106 MeV. If this is the only energy input necessary to initiate muon-catalyzed fusion, how many reactions must a muon catalyze to attain the break-even point?

    2. Relevant equations

    3. The attempt at a solution

    from the previous question, I got the energy per reaction is 17.6 MeV
    so, the number of reactions needed = 106 / 17.6 = 6 reactions
    but the feedback says that "This is very close to releasing the same amount of energy as was input, but we want more energy than was input."
    I'm totally confused..

    please help me..
  2. jcsd
  3. Apr 21, 2008 #2
    I think they want you to round up.
  4. Apr 21, 2008 #3
    the real answer is 6.022,
    I already rounded up to 6..
  5. Apr 21, 2008 #4
    No, you rounded down. ;)
  6. Apr 21, 2008 #5
    oh my.. thank you so much to Phlogistonian.. :)
  7. Apr 21, 2008 #6
    Based on your answer, I guess they just wanted more significant figures. We didn't use these computer things when I was in school. We just used books, pencil, and paper. :)
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