$(3)$ A closed cylindrical tank is $3\mathrm{.}5m$ high and contains an oil of relative density $0\mathrm{.}85$ to a height of $3\mathrm{.}0m$ above the bottom. The space above the oil surface contains air under a pressure of $50$kPa. If an $8cm$ diameter orifice is provided on the side of the tank with its centre $25cm$ above the bottom, estimate the weight of fluid discharged in one minute $.($take $C_d=0\mathrm{.}6)$

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