b$)$ In a single$-$screw extruder the dimensions of the channel are :

Diameter $(D)=5\mathrm{.}03cm.$ Width $(w)=1\mathrm{.}1cm,$ Height $(H)=0\mathrm{.}36cm,$ Screw Angle $()=6\mathrm{.}3.$ speed of Rotation $=10$ revolution per second $($ rps $)$

Assume a flat plate model in the melt zone of a single$-$screw extruder $\frac{\text{d}\text{e}\text{l}\text{P}}{\text{d}\text{e}\text{l}\text{z}}=\frac{de{l}^2{v}_n}{del{y}^2}*v_n=0$ at $y=0$ and $v_z=v_m$ at $y=H$