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Thread: Vectors: Magnitude of forces acing on stable object: A = 800kN, B = 650kN, so C = ?

  1. #1

    Vectors: Magnitude of forces acing on stable object: A = 800kN, B = 650kN, so C = ?


    Having great difficulty in the following problem:

    Magnitude of the 3 forces acing on a stable object

    A = 800kN
    B = 650kN
    C = ?

    What is the magnitude of force C?

    Any feedback would b much appreciated.
    Many thanks.

  2. #2
    Elite Member
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    Quote Originally Posted by NAC54321 View Post

    Having great difficulty in the following problem:

    Magnitude of the 3 forces acing on a stable object

    A = 800kN
    B = 650kN
    C = ?

    What is the magnitude of force C?

    Any feedback would b much appreciated.
    Many thanks.
    Forces are vectors. Those need to have three characteristic properties, when applied to a body. Those are:

    Magnitude

    Direction and

    point of application.

    You have given us only one of those (magnitude for A and B).

    You need to define the other two in the problem statement before this problem can be solved.
    “... mathematics is only the art of saying the same thing in different words” - B. Russell

  3. #3
    Hi Khan,

    Thanks for the reply.
    Unfortunately the question has very limited numbers, no angles etc.
    The object is stable what is the magnitude of force C?

    Please see below,
    Many thanks.


  4. #4
    Elite Member stapel's Avatar
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    Cool

    Quote Originally Posted by NAC54321 View Post
    Unfortunately the question has very limited numbers, no angles etc.
    The object is stable what is the magnitude of force C?

    Please see below,

    The "below" is not displaying for the rest of us. Also, without any further information (than just the magnitude of two of the forces), there is no way to answer this question. Sorry!

  5. #5
    Hi all,

    I have tried to attach a basic sketch of the question.
    Apart from west, south directions,
    Magnitude A(west) = 800 kN
    Magnitude B (south)= 650 kN
    Magnitude C (figure shows approximate direction it says) = ?

    Thankyou
    Attached Images Attached Images
    • File Type: jpg 1.jpg (6.7 KB, 1 views)

  6. #6
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    Quote Originally Posted by NAC54321 View Post
    Hi all,

    I have tried to attach a basic sketch of the question.
    Apart from west, south directions,
    Magnitude A(west) = 800 kN
    Magnitude B (south)= 650 kN
    Magnitude C (figure shows approximate direction it says) = ?

    Thank you
    That sketch makes the problem solvable!

    Have you been taught about Cartesian unit vectors?
    “... mathematics is only the art of saying the same thing in different words” - B. Russell

  7. #7
    Elite Member stapel's Avatar
    Join Date
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    Cool

    Quote Originally Posted by NAC54321 View Post
    Apart from west, south directions,....
    Yes; directions; that's exactly what we'd been asking for!

    Your unfamiliarity with how vectors work suggests that you might not be entirely familiar with what they are, or with how to solve this sort of exercise...? Do you need lesson links, so you can study up on this topic?

    Thank you!

  8. #8
    Thanks for both replies, much appreciated.
    I've done basic vectors in lectures but nothing like the above.
    I clearly need to study up on this, any clear direction to study which would help me answer this question would be good.

    Are you both saying that this problem is more than just a magnitude formulae?

    What are the clear steps to solve this problem? Also determine angles etc? I understand that there is a 90 degree difference between A &B, just struggling with what the other steps that are required?

    Again, thanks for your continued help.

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