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Homework Help: Total energy of an oscillator

  1. Apr 9, 2007 #1
    1. The problem statement, all variables and given/known data

    A mass M is suspended from a spring and oscillates with a period of .940s. Each complete oscillation results in an amplitude reduction of a factor of .96 due to a small velocity dependent of frictional effect. Calculate the time it takes for the total energy of the oscillator to decrease to .50 of its initial value.

    2. Relevant equations

    unsure.... A=Ao*factor^N
    3. The attempt at a solution

    I am unsure how to approach this. I did

    log .50 = t log(.96)^2
    t= log(.50)/log(.96)^2
    t=8.48 s

    but that was incorrect. Can someone please tell me what I am doing wrong?
  2. jcsd
  3. Apr 9, 2007 #2


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    Science Advisor
    Homework Helper

    In you equation

    log .50 = t log(.96)^2,

    "t" isn't the time in seconds, it's the number of cycles of oscillation when the energy has decayed to .50 of the original value.

    You want to time for 8.48 cycles with a period of 0.940 sec/cycle.
  4. Apr 9, 2007 #3
    Oh, I see now. I think I can handle the equation from here. Well, I'm going to attempt the problem again to make sure :smile:
  5. Apr 9, 2007 #4
    Yes, I got it correct, thank you AlephZero!
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