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Homework Help: Force acting on steel rod (deformation)

  1. Jun 24, 2016 #1
    in this problem , i could only understand that P3 = 120KN , i cant understand why P2= -60kN and why P1 = 240kN ? can someone explain ?

    2. Relevant equations

    3. The attempt at a solution

    Attached Files:

  2. jcsd
  3. Jun 24, 2016 #2


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    In the same way that you can do a shear force diagram for lateral loads on a beam you can do a tension force diagram for axial loads on a shaft .

    Basically plot a graph of axial tension against position along shaft . Have a try .
  4. Jun 24, 2016 #3
    What do you mean? can you explain further?
  5. Jun 24, 2016 #4
    If you do a force balance on the entire rod, what do you get for the reaction force on the left end?
  6. Jun 24, 2016 #5
    how to do it ? i know only the P3 .... which is 120kN , how to do for P1 and P2 ?

    Attached Files:

    • 229.png
      File size:
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  7. Jun 24, 2016 #6
    You have 3 forces acting on the rod: 300 kN, 180 kN, and 120 kN. In order of the rod to be in static equilibrium, there must also be a force applied by the wall on the bar at location A. What does that force have to be?
  8. Jun 24, 2016 #7
    what i found is this ? how to find the force applied by the wall on the bar at location A. ??
    btw , i am not sure which 1 is P3 and which one is P2

    Attached Files:

    • 230.jpg
      File size:
      25.1 KB
  9. Jun 24, 2016 #8
    Forget about P1, P2, and P3 for now. Are you saying that you don't know how to do a 1 dimensional equilibrium force balance on a solid object?
  10. Jun 24, 2016 #9
  11. Jun 24, 2016 #10

    F = 300 -180 + 120
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