For the state of stress defined in Example 3, determine the magnitudes and direction cosines of the principal stresses.
(Answers: 147.4 /m²,=+0.7382,m=+0.1266,=+0.6625;76.6 /m²,=-0.6456,m=+0.4172,=+0.6397;-86.1 / m²,= +0.1954,m=+0.9000,=-0.3897.)
from the principal stress.
₁=-86.05/m²
₂=147.4,m/m²
₃=76.61,/m²