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Homework Help: Non-calculus based general physics question

  1. Feb 1, 2006 #1

    I was wondering if someone could help me with a homework problem for non-calculus based physics:

    Two crewmen pull a boat through a lock. One crewman pulls with a force of F1 = 150 N at an angle of 32 degrees relative to the forward direction of the boat. THe second crewman, on the opposite side of the lock, pulls at an angle of 45 degrees. With what Force F2 should the second crewman pull so that the net force of the two crewmen is in the forward direction?

    F1 is F subone and F2 is F subtwo

    THank you for your help!:confused:

    I worked the problem out by this but have the wrong answer:

    F = -F1Sintheta1/Sintheta
    = -(150N)sin32 degrees/sin(-45degrees) = 116N

    the computer program is saying this is wrong.

    I tried 120N to maybe b/c sig figs. Not sure

  2. jcsd
  3. Feb 1, 2006 #2


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    HINT: If the boat is travelling in the y direction then what is the x component of the force exerted by the first crewman.
  4. Feb 2, 2006 #3

    I am not sure. That might be the solution to my problem, but I just can't figure it out. Can you help me? Thank you for your time and input.

  5. Feb 2, 2006 #4
    redefine your coordinate system so that the forward direction of the boat is the x-axis. Then redraw your force vectors, break them into components and try to solve again.

    Draw a picture it really helps.
  6. Mar 25, 2007 #5
    if the answer is 179.9N approximately 180N and u need a detailed solution email me at demooreonline@yahoo.com with the subject physics: question.
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