All pipes are $8-cm-$diameter cast iron. Determine the flow rate from reservoir $(1)$ if valve C is

$($a$)$ closed; and $($b$)$ open, with $K_{\text{v}\text{a}\text{l}\text{v}\text{e}}=0\mathrm{.}5.$

Properties: For water at $20C,$ take $=998k\frac{g}{m^3}$ and $=0\mathrm{.}001k\frac{g}{m}*s$

Assumption: $P_1=P_2,V_l=V_2$~~$0$

Note: Minor losses need to be considered.