Stress on a plane

Hi all, for some reason I cannot get this to work out. I need to solve for shear and normal stresses on an arbitrarily oriented plane in 3-dimensions given a symmetric stress tensor and the normal vector to the plane. So far as I can figure it is easiest to take the dot product of each principal stress vector and the normal vector, but then how do I resolve that into shear and normal stress on the plane?

Thanks in advance for any advice. :confused:

Welcome to EE!

You need to post a free body diagram...

Do I really need to post a free body diagram, or is that a way of hazing me into the forum? Haha, but really, I think I have this figured out just doing stress transformation. I still feel like I should be able to do it using the normal vector to the plane and taking the sum of the dot products....

[QUOTE=Edogg;5966]Do I really need to post a free body diagram[/QUOTE]

Oh course you do... While you're at it post the calculations you have done so far..