$2).(7$ points$)$ Draw Mohr's Circle and find the center, the radius, principal stresses, the rotation angle in the Mohr's Circle plane, and the physical angle in the physical plane.

$($Please check the direction of stresses on the stress plane; Sign of stress$)$

$3).(4$ points$)$ Calculate the physical angle in the physical plane and principal stresses for pure shear loading.

$($Please draw Mohr's Circle and distinguish whether the normal stresses in the principal stress are tension or compression$).$

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