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Homework Help: Mechanics help !

  1. Oct 29, 2005 #1
    Mechanics help plz!

    Hi, can anyone help me with the following mechanics question:


    I've attempted this question but I'm stuck on how i can prove that θ = 45° :confused:

    I've constructed a diagram but I havent scanned it but what i've got so far is from the diagram at point C, by resolving horizontally i find that the tensions, say T1 and T2 are equal to each other and I label this as T.

    Resolving vertically I get 2T cos θ - w = 0

    for the bead on the far left, by resolving horizontally I got:

    F1 - T1 sin θ = 0 (F1 being the force acting towards the left)

    vertically I get: N1 - T1 cos θ - w = 0

    For the bead on the far right
    , by resolving horizontally I get:

    F2 - t2 sin θ = 0


    N2 - T2 cos θ = 0

    And this is where I'm stuck...I don't know where to go from here. Am I on the rght track? Can anyone help? Thanks! :confused: Sorry again that I havent provided my diagram :frown:
    Last edited by a moderator: Apr 21, 2017
  2. jcsd
  3. Oct 29, 2005 #2

    Physics Monkey

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    Ok, a couple things here that you need to work on.

    Sorry, I misread the question, ignore my first comment (which I have now deleted).

    Second, you left out the weight in the vertical force equation for the point B on the far right.

    Third, you need to figure out how the condition that the beads A and B be as far apart as possible plays into things. Here is a hint: what is the maximum horizontal force of friction that bead A can feel? What about bead B?
    Last edited: Oct 29, 2005
  4. Oct 29, 2005 #3
    hmm I still don't understand...:confused:
  5. Oct 29, 2005 #4

    Physics Monkey

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    Where does the horizontal force on bead A that balances the tension come from? What is the maximum value this force can have? Answer the same thing for B.
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