$5\mathrm{.}8(10$ pts$)$ A $10$ mm diameter cylindrical zinc single crystal has a longitudinal axis that makes an

angle of $85$ with the pole of the basal plane and a $7$ angle with the closest $($:$\frac{11}{b}ar(2)0$:$)$ slip direction in

the basal plane. If the critical resolved shear stress of zinc is $0\mathrm{.}20$ MPa $,$ at what axial load should the

crystal begin to deform by basal slip in:

$($a$)$ Newtons.

$($b$)$ Kilograms force.