Mechanics

No, I ask about the normal stress in Y , why its 0 

90 comes from T which was calculated earlier in the solution   The shaft (solid)diameter was stated to be 25mm ....or a RADIUS of 0.0125 m    which would be the 'arm' the torque operates through....      J he calculated in the previous step.

I am not sure,   does this answer your question?

~jc 

Hi 315, 

I have reasked your question here 

http://web2.0calc.com/questions/but-why-is-it-0-re-asked-question

Are you talking about the last line displayed in your question, where he says Stress at point H is zero then the component  oy = 0   ?        Can you scan in the rest of the solution below that point?   For those of us a little rusty on physics it may help us answer ....right now all I can see is that the y components are cancelling, but it might help me to figure this out if I could see the rest of the solution...... sorry ...for now   ~jc     Didn't we see this problem before????

Thank you melody :) 

This is the rest of the solution 

JC! You are like an eel! Why can't u stay on long enough for me to find u? Make an account plz!