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Homework Help: Flagpole help

  1. Jun 8, 2005 #1
    A uniform, horizontal flagpole of length 5.00 m and with a weight of 195 N
    is hinged to a vertical wall at one end. A stuntwoman weighing 600 N hangs
    from its other end. The flagpole is supported by a guy wire running from
    its outer end to a point on the wall directly above the pole.

    a) If the tension in this wire is not to exceed a force of 1070 N, what is
    the minimum height above the pole at which it may be fastened to the wall?

    b) If the flagpole remains horizontal, by how many newtons would the
    tension be increased if the wire were fastened a distance 0.520 m below
    this point?

    For a) I got 4.30m by tan(theta) = d/5m solve for theta then for d

    How do I solve for b)?
  2. jcsd
  3. Jun 8, 2005 #2
    I used theta = arctan(d/x) = arctan(4.3/.52m) = 83.1 but it gives me a rounding off error
  4. Jun 9, 2005 #3


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    Science Advisor
    Homework Helper

    Your new angle is the solution to

    tan(theta) = (d-.52m)/5m

    where d is the 4,30m from the first part. With your new angle, you can still equate the magnitude of the torque of the wire to the magnitude of the torque of the pole plus the woman.
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