$7\mathrm{.}13$ through $7\mathrm{.}16$ For the given state of stress, determine the normal and shearing stresses after the element shown has been rotated through $($a$)25$ clockwise, $($b$)10$ counterclockwise.

Fig. P$7.13$

Fig. P$7.14$

Fig. P$7.16$

$448$