How to calculate average stress?

[physea]

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!

 

[Joppy]

Might be just me, but i can't open that image.

 

[physea]

OK the free body diagram is this;

 

[Joppy]

What do you think it is

 

[physea]

I think it's zero, because at that point, the two opposite forces are cancelling each other

 

[berkeman]

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.

 

[SteamKing]

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:

​

 

[physea]

ok then it's 16sin60

 

[SteamKing]

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?