How to calculate average stress?

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    Average Stress
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Discussion Overview

The discussion revolves around calculating average normal stress in a specific scenario involving forces and a free body diagram. Participants are trying to determine the correct expression for average normal force and its implications for average normal stress.

Discussion Character

  • Debate/contested

Main Points Raised

  • One participant questions whether the average normal force should be calculated as 8sin60, 16sin60, or 0.
  • Another participant reports an inability to access an attached image that may provide context.
  • A participant presents a free body diagram to aid in the discussion.
  • Several participants express the view that the average normal force is zero, arguing that opposing forces cancel each other out at that point.
  • One participant acknowledges that while the average normal force may be zero, the stress is not zero due to forces acting on the bar.
  • Another participant suggests that the correct average normal force is 16sin60, but this is met with skepticism regarding the origin of the sin 60 factor and the definition of stress.

Areas of Agreement / Disagreement

Participants express differing opinions on the value of the average normal force, with some asserting it is zero and others proposing it is 16sin60. The discussion remains unresolved with multiple competing views present.

Contextual Notes

There are unresolved questions regarding the definitions and calculations of stress and normal force, as well as the context provided by the free body diagram.

physea
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hello!

In the question below, is the average normal force in order to calculate the average normal stress, 8sin60 or 16sin60 or 0?

https://www.physicsforums.com/attachments/stress-jpg.100364/

thanks!
 
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Might be just me, but i can't open that image.
 
OK the free body diagram is this;

upload_2016-5-7_2-48-56.png
 
What do you think it is
 
I think it's zero, because at that point, the two opposite forces are cancelling each other
 
physea said:
I think it's zero, because at that point, the two opposite forces are cancelling each other
The stress is not zero because there are forces pulling the bar apart.
 
physea said:
I think it's zero, because at that point, the two opposite forces are cancelling each other
Ask this guy if the stress is zero:


10919259-Man-Being-Tortured-On-The-Rack-Stock-Photo-torture-rack.jpg

 
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ok then it's 16sin60
 
physea said:
ok then it's 16sin60
No, it isn't.

Where does the sin 60 come from?

Do you know what the definition of "stress" is?
 

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