Q$2$: Experimentally, it has been observed for single crystals of a number of metals that the critical resolved shear stress, $$ crss$,$ is a function of the dislocation density, $D,$ as

${}_{crss}={}_0+A\sqrt[\phantom{2}]{{}_D}$

where $0$ and A are constants. For some metal, the critical resolved shear stress is $3\mathrm{.}44$ MPa at a dislocation density of $1\mathrm{.}26104mm-2.$ If it is known that the value of A for this metal is $3\mathrm{.}9110-3$MPa$*mm,$ compute the in MPa