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Homework Help: Physics Trigonometry Problem.

  1. Sep 14, 2006 #1
    Hello, I am currently in beginning physics and we are learning a lot about Trig onometry. A homework problem is really bugging me. Here's what it says:

    Find the angle A, given the altitude and arc length of the figure shown:
    (the picture is in the attachment and also some work i have done.)
     

    Attached Files:

  2. jcsd
  3. Sep 14, 2006 #2
    testing if i can put the image on this post.
    http://img222.imageshack.us/img222/6819/physicszw2.gif [Broken]
     
    Last edited by a moderator: May 2, 2017
  4. Sep 15, 2006 #3

    andrevdh

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    Homework Helper

    I can also solve it only numerically for the ratio

    [tex]\frac{\sin(A)}{A}=0.719[/tex]

    which gives A as 0.8658 radians
     
    Last edited: Sep 15, 2006
  5. Sep 15, 2006 #4

    J77

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    When you say you "believe the hypotenuse is the radius"... it doesn't look it in your sketch.
     
    Last edited: Sep 15, 2006
  6. Sep 15, 2006 #5

    HallsofIvy

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    Basically, then, you have a circular arc, of length 4.17 cm. Dropping a perpendicular gives a length of 3 cm. Yes, the hypotenuse of the right triangle is a radius of the circle. sin A= 3/R and, as long as A is measured in radians, RA= 4.17. Since R= 4.17/A, putting that into the first equation you have sin A= 3A/4.17 just as you say. There is no "algebraic" way of solving such an equation. A numerical solution is the best you can do.
     
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