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Homework Help: Using moment of inertia to get angular speed

  1. Dec 14, 2012 #1
    1. The problem statement, all variables and given/known data

    Hiya boys,

    Sorry i dont know how to proceed with this problem can anyone help me solve these two questions?

    In preparation for building a space station, an astronaut removes a self-telescoping uniform rod from the cargo bay and releases it, not noticing that he gave it an angular speed of 0.0500 radians per second. The pole is 3.00 meters long. A catch slips, and the pole spring retracts it into a shorter 1.50 meter long uniform pole about a minute after the astronaut releases it.
    Find the angular speed after the catch slips.

    2. Relevant equations

    I = mr^2/12 or mr^2/3

    ω = v/r

    3. The attempt at a solution

    Iinitial = Ifinal
    m (3^2)/12 = m (1.5^2)/12

    m= do i need this?

    (0.05)(x) = ω
  2. jcsd
  3. Dec 14, 2012 #2


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    Science Advisor
    Homework Helper
    Gold Member

    What are Iinitial and Ifinal here? The eqn can't be right since it reduces to 4 = 1.
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