Civil engineering very simple question

Replies

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  Ramani Aswath

  There is nothing Civil Engg about this. Lbs and meters are mixed in the problem. Does not matter.
  The torque on the pivot C will be 6000 x 5 (Distance of CG of bar from pivot) This will be equal to the sum of the tension loads in the cable at A and B. The vertical force at A will have to take into account the angle the cable makes at A (Hence 3/sqrt(34)).
  The tensile load divided by the area of the cable gives the value for stress.
• 

  Worapat Sopa

  A.V.Ramani

  There is nothing Civil Engg about this. Lbs and meters are mixed in the problem. Does not matter.
  The torque on the pivot C will be 6000 x 5 (Distance of CG of bar from pivot) This will be equal to the sum of the tension loads in the cable at A and B. The vertical force at A will have to take into account the angle the cable makes at A (Hence 3/sqrt(34)).
  The tensile load divided by the area of the cable gives the value for stress.

  
  Thank you very much. I have forgotten a lot of math over the last few years. May i ask about the part "(Hence 3/sqrt(34))" ? I assume it has something to do with Pythagoras.
• 

  Ramani Aswath

  Worapat Sopa

  I assume it has something to do with Pythagoras.

  Exactly. If you look at the small right triangle under solution youcan see that the vertical component of the tension acting along the slanting cable is equal to 3/sqrt(34). The sum of vertical upward moments should be equal and opposite to the torque on the bar if unsupported.