(adsbygoogle = window.adsbygoogle || []).push({}); Stress -- Cross-sectional and Inclined planes

As per attachment...

"On the cross-sectional plane mm the uniform stress is given

by P/A, while on the inclined plane mm the stress is of magnitude P/A'. In both cases

the stresses are parallel to the direction of P."

The parallel part makes sense... what doesn't to me is why even bother with the inclinded plane stress measured from area A'... shouldn't we just use A because if you're looking paralell to the force P, area A' will look like area A? After all, if you pick a point (say right in the middle of our solid spar or rectangular thing as per image) then you can draw an infinite amount of planes around that point at their correspondingly infinite numbers of angles... however no matter what plane you select, you'll end up with the same force being applied. Why even bother with non perpendicular planes?

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# Aerospace Stress - Cross-sectional and Inclined planes

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