$($a$)$ A large, open at the top, upright cylindrical tank contains a brine with a density of $1\mathrm{.}23$ xx$10^(3)$kg$//$m$^(3).$ If the air pressure is $101\mathrm{.}3$ kPa $,$ determine the absolute pressure $($in Pa$)$ in the fluid at a depth of $23\mathrm{.}0$ m

$($b$)$ Determine the force $($in N $)$ exerted by only the fluid on the window of an instrument probe at this depth if the window is circular and has a diameter of $3\mathrm{.}45$ cm $.$