Free Body Diagram for simply supported beam

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Discussion Overview

The discussion revolves around drawing a free body diagram (FBD) for a simply supported beam, focusing on identifying and representing the forces acting on the beam. The scope includes homework-related inquiries and technical reasoning regarding the forces involved.

Discussion Character

  • Homework-related, Technical explanation, Debate/contested

Main Points Raised

  • One participant outlines the forces F1 and F2 in the FBD and notes the need for additional forces at points A and B to maintain equilibrium.
  • Another participant points out that there is a missing force at point A, suggesting that both horizontal and vertical forces should be present due to the pin support.
  • A different participant argues that only one force can be drawn at point A, referencing an attached image for clarification.
  • There is a suggestion to represent the resultant of the horizontal and vertical forces at point A as a single angled force.
  • A participant expresses gratitude for the clarification and acknowledges the possibility of representing multiple forces at one point in the diagram.

Areas of Agreement / Disagreement

Participants exhibit disagreement regarding the number and types of forces that should be represented at point A, with some asserting the necessity of multiple forces while others maintain that only one is appropriate. The discussion remains unresolved.

Contextual Notes

There are limitations in the assumptions made about the forces acting on the beam, particularly regarding the representation of forces at point A and the interpretation of the FBD.

Kasthuri
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Homework Statement



As shown in the attachment, a free body diagram (FBD) must be drawn

Homework Equations



sum of horizontal force = 0
sum of vertical force = 0

The Attempt at a Solution



1. Forces F1 and F2 appear exactly as they are in the FBD

2. At point A, there is an outward horizontal force : <----- A, to counteract F2

3. At point B, there is an upward force to counteract F1 :

B
^
|
|
|

However, I think I have done something wrong. Any help would be greatly appreciated!
Thanks
 

Attachments

  • beam.JPG
    beam.JPG
    9.6 KB · Views: 2,545
Last edited:
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Kasthuri;4009649 3. At point B said:
You are missing a force at point A.
 
That's what I thought too, because it's pin supported, there should be a horizontal and vertical force acting at point A. But I attached another picture that shows where to draw the forces. And there's only one force that can be drawn at point A.

Also all the circles don't have to have forces drawn on them, so I left the middle circle.
 

Attachments

  • beamForce.JPG
    beamForce.JPG
    3.1 KB · Views: 627
Why not draw it at an angle representing the resultant of the horiz and vert forces ?
 
ok thank you Cwatters and phanthomJay. I found it was possible to more than one force on one circle.
 

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