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Rotational equilibrium help on problem

  1. Jan 6, 2007 #1
    i have a homework problem that i could use some help on.
    i have read the entire chapter and all of my notes from class. i have studdied everything i had and have had no luck. so if you can help that would be GREAT!! i have done the first step of drawing a picture and i think for the given: the mass=20.0kg, \theta=30.0 degrees and for part a you are looking for the force. other then that i do not know how to get started on this problem. if you could help get me started that would be wonderful. i dont know what kind of formula to use. so PLEASE help if you can.

    A floodlight with a mass of 20.0kg is used to illuminate the parking lot in front of a library. the floodlight is supported at the end of a horizontal beam that is hinged to a vertical pole. a cable that marks an angle of 30.0 degrees with the beam is attached to the pole to help support the floodlight. find the following, assuming the mass of the beam is negligible when compared wiht the mass of the floodlight.
    a) the force provided by the cable
    b)the horizontal and vertical forces exerted on the beam by the

  2. jcsd
  3. Jan 6, 2007 #2


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    Staff Emeritus
    Science Advisor

    Attempt the other question first, following my hints. Then use your knowledge to have a go at this one!
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