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I insert in my calculator cos 50x60 = 42.42

  1. Dec 11, 2011 #1
    1) cos 60o = vx0 / 50 => vx0 = 50.cos 60o = ?
    2) sin 60o = vy0 / 50 => vy0 = 50.sin 60o = ?



    OK so I use my calculator for 1) and I insert in my calculator cos 50x60 = 42.42 but this is not the right answer because the answer is 25 m/s because the answers are in the back of my book.

    FOr question number 2) I not 100 % sure but I do the same thing sin 50x60 = 42.42 in this case I get the same answer than in cos, and the answer is 43 m/s so I dont know about this because I got 42.42 so maybe this is right.
     
    Last edited: Dec 11, 2011
  2. jcsd
  3. Dec 11, 2011 #2

    gneill

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    Staff: Mentor

    Re: Trigonometry

    What does your calculator give you for cos(60°) ?
     
  4. Dec 11, 2011 #3
    Re: Trigonometry

    0.5877 ... but then I restart my calculator and I get 0.5
     
  5. Dec 11, 2011 #4

    gneill

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    Staff: Mentor

    Re: Trigonometry

    Your calculator was set to treat angles in 'grads' rather than degrees. There are 400 grads in a circle of 360 degrees.
     
  6. Dec 11, 2011 #5
    Re: Trigonometry

    But now that I restarted I get in cos 38.567 but I don't get 25 m/s .... and in sin I get now 45.96 and I suppose to get 43 m/s :(
     
  7. Dec 11, 2011 #6

    gneill

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    Staff: Mentor

    Re: Trigonometry

    More finger problems :smile:

    You've taken the cosine of 50 degrees and multiplied by 60 rather than take the cosine of 60 degrees and multiply by 50.
     
  8. Dec 11, 2011 #7
    Re: Trigonometry

    YEAHHH!!! Thanks!!! :)
     
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