Consider water at $4C$ flowing through a $300$ mm diameter pipe at $6\frac{m}{s}.$

a$.$ If pipe is galvanized iron, obtain relative roughness, the approximate friction factor $f$ and state the flow regime $($turbulent$,$ laminar or transition$)(1$ point$)$

b$.$ If the pipe is rough cast concrete, obtain relative roughness, the approximate friction factor $f$ and state the flow regime $($turbulent$,$ laminar or transition$)(1$ point$)$

c$.$ If the Reynolds is number less than $2000,$ which pipe will have a higher friction factor f $?$ points$)$