A rectangular polymer plate of dimensions $a=163mm$ and $b=371mm$ is formed by gluing two triangular plates as shown in the figure. The plate is subjected to a tensile normal stress of $10\mathrm{.}7$ MPa in the long direction and a compressive normal stress of $5\mathrm{.}6$ MPa in the short direction. Determine:

$($a$)$ the normal stress perpendicular to the glue seam.

$($b$)$ the shear stress parallel to the glue seam.

$($a$)$ Enter the normal stress ${}_n$ perpendicular to the glue seam. This is the normal stress in the $n-$ direction which is normal to the inclined plane as shown in the figure below. Use the correct sign based on the sign convention for normal stress.

${}_n=$

MPa

$($b$)$ Enter the shear stress parallel to the glue seam. Your answer must be consistent with the sign convention for shear stresses and the $n-t$ coordinate system shown in the figure above.

${}_{nt}=MPa$