b$)$ Pair the items in the column I with those in the column II$.$

Column I

Column II

$($Processing step$)$

$($Item$)$

i$)$ rotational molding

polyurethane

ii$)$ extrusion

use of a gas

iii$)$ reaction injection molding

centrifugal force

iv$)$ blow molding

twin screw

c$)$ An aligned short carbon fiber reinforced polyester composite has a fiber content of $40\%$ by volume. The elastic modulus of the carbon fiber and the polyester resin are $250$ GPa and $35$ GPa respectively. The fiber diameter is $5m$ and the ultimate tensile strength of the fiber is $1240$ Mpa $.$

i$)$ Find the modulus of the composite.

ii$)$ The fiber$-$matrix bond strength, assuming a critical fiber length of $12$ mm $,$ is $$ MPa $.$