$($Flowrate$)$ Water flows through the pipe contraction shown in the figure below. For the given $0\mathrm{.}21-$m difference in manometer level, determine the flowrate.

$\backslash [$

$\backslash$mathrm$\{$m$\}\backslash$sim $/\backslash$mathrm$\{$s$\}$

$\backslash ]($Bernoulli$/$continuity$)$ Water flows steadily through the pipe shown in the figure below such that the pressures at sections $(1)$ and $(2)$ are $343$ kPa and $81$ kPa $,$ respectively. Determine the diameter of the pipe at section $(2),\backslash ($ D$\_\{2\}\backslash ),$ if the velocity at section $1$ is $\backslash (18\backslash$mathrm$\{$~m$\}/\backslash$mathrm$\{$s$\}\backslash )$ and viscous effects are negligible.