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Homework Help: Force (Can someone check what I did wrong)

  1. May 3, 2005 #1
    Can you tell me what I did wrong.

    I posted it on photobucket:

    http://img.photobucket.com/albums/v228/LianaBlank/img003.bmp [Broken]
     
    Last edited by a moderator: May 2, 2017
  2. jcsd
  3. May 3, 2005 #2

    arildno

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    Could you magnify it a bit?
    It is difficult to read the text.
     
  4. May 3, 2005 #3
    Well, it's a little bigger, but still kind of small

    http://img.photobucket.com/albums/v228/LianaBlank/cc5a5559.bmp [Broken]

    Basically, I know that
    I = 5 A
    B= 0.5 T
    the sides of the loop are 0.05 m long
    The loopp was rotated around the Y axis and makes a 60 degree angle with the X-Y plane

    I must find the Force on side A-B.

    My answer (0.0625) is 1/2 of the correct answer (0.125).
     
    Last edited by a moderator: May 2, 2017
  5. May 3, 2005 #4

    Doc Al

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    If the B field is in the + z direction, then what's the angle between that B-field and side a-b? It's not 60 degrees!
     
  6. May 3, 2005 #5
    I used 30 degrees (angle between B and A-B)... Is that correct?
     
  7. May 3, 2005 #6

    Doc Al

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    No, it's not. (For some reason I thought you used 60 degrees... sorry about that!) Hint: the line A-B is parallel to the Y-axis.
     
  8. May 3, 2005 #7

    Doc Al

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    Note that 30 degrees is the angle that the plane of the loop makes with the B-field. It is not the angle between the B-field and the line segment A-B!
     
  9. May 3, 2005 #8
    Oh ok. It's at 90 degrees from B then. That makes more sense. Basically, the side that is 30 degrees from B is the bottom wire right?

    Thanks for your help
     
  10. May 3, 2005 #9

    Doc Al

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    You got it.
     
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