$8\mathrm{.}10$ Given the data of Example $8\mathrm{.}4.($a$)$ Find the magnitude and direction of the stresses on the vertical plane passing through this point. $($b$)$ Find the maximum shear stress, and determine the angle between the plane on which it acts and the major principal plane.

Example $8\mathrm{.}4$

Given

The stress on an element shown in Fig. Ex$.8\mathrm{.}4$a$!.$

Figure Ex$.8\mathrm{.}4$

$($a$)$

$($b$)$