Question $2$

The plane ab$,$ bc and ac shown below are in a stressed material.

Calculate:

$2\mathrm{.}1$ The value of the unknown shear stress. $($From first principals$)$

$2\mathrm{.}2$ The magnitude of the principal stresses and the maximum shear stress.

$2\mathrm{.}2$ The magnitude of the principal stresses and the maximum shear stress.

$($Use standard formula$)$

$(7)$

$2\mathrm{.}3$ Use Mohr's stress circle to verify your results in $2\mathrm{.}1$ and $2\mathrm{.}2$

$(8)$

$(16)$

$[31]$