Recent content by otonh210

  1. O

    Rotational Frequency [figure skater]

    Ah. I have clearly absorbed nothing from the lessons on rotation. So, Iarm = 1/12 (5kg)(.66m^2) + (5kg)(.43m^2) Iarm = 1.106 wf = 5.804 rev/s
  2. O

    Rotational Frequency [figure skater]

    Okay. I thought you had to use the rod about one end, because they are attached to the torso which is rotating. Thank you SO much for your help though. I appreciate it a lot!
  3. O

    Rotational Frequency [figure skater]

    For Iarm I did, Iarm = (1/3)(m)(r^2) + (m)(d^2) Iarm = (1/3(5kg)(.66m^2) + (5kg) (.43m^2) Iarm = 1.6505 then, [Ibody + Iarm]/Iwholebody = wf [0.2 + 1.6505]/0.225 = 8.22 rev/s
  4. O

    Rotational Frequency [figure skater]

    Ah, Mastering Physics is a program that comes with 'Physics for Scientists and Engineers' to help people study. Author for Physics for S&E is Randall D Knight, I believe. Thank you very very much for your assistance! I am now getting 8.22 rev/s as a final answer. Does this sound more...
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    Rotational Frequency [figure skater]

    For my Physics class, we have sets of problems that we must hand in each week. They tell us the answers, so that we know we are doing it correctly [but not how to get there]. The answer they gave us for this problem was 3.5 rev/s. It appears to be 12.90, but I am unsure of which textbook...
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    Rotational Frequency [figure skater]

    Is Parallel Axis Theorem Ic + MD^2? I tried the above, with many different Ds, but none seemed to give me the right answer. Yes, that is a typo. It is supposed to be 1.0 rev/s Each arm has a mass of 2.5 kg. The person mentioned to me that they got the correct answer by pretending it was...
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    Rotational Frequency [figure skater]

    I tried the math above, and it does not work. Do I need to use a different equation for the arms? Ibody+MD^2 (?) If so, what do I use for D? The distance from the edge of the torso to the axis of rotation? The distance from the centre of mass of the arm to the axis of rotation? The...
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    Rotational Frequency [figure skater]

    I'm unsure of how to apply the Parallel Axis Theorem, because I've never heard of it until now. Do I just add the distance from the outside of the torso [attachment point] to the axis of rotation? Iarm = 1/3(m)(l+r)^2? Iarm = 1/3(2.5kg)(.66m+.1m)^2 Iarm = 0.4813 Ibody = 1/2(40kg)(.1m^2) Ibody =...
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    Rotational Frequency [figure skater]

    Homework Statement A 45kg figure skater is spinning on the toes of her skates at 1.0 rev/s. Her arms are outstretched as far as they will go/ In this orientation, the skater can be modeled as a cylindrical torso (40kg, 20cm average diameter, 160cm tall) plus two rod-like arms (2.5kg each, 66cm...
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