Q$-3/$

$/$ In Fig. below, fluid A is water and fluid B is oil $($sp$.$ gr$.0\mathrm{.}85).$ If $h=69cm,$ and $z=23cm,$ what is the difference of pressure in $k\frac{N}{m}2$ between M and N $?$

Q$-4/$ A $20$mm diam pipe forks, one branch being $10$ mm in diam and the other $15$ mm diam. If the velocity in the $10$ mm pipe is $0\mathrm{.}3\frac{m}{s}$ and that in the $15$ mm pipe is $0\mathrm{.}6\frac{m}{s},$ calculate the velocity in $\frac{m}{s}$ and the rate of flow in $c\frac{m^3}{s}$ in the $20$ mm diam pipe.

$(129\mathrm{.}6c\frac{m^3}{s},0\mathrm{.}413\frac{m}{s})$

Q$-5/$ A fluid of constant density flows at the rate of $15$ litres$/$sec along a pipe AB of $100$ mm diam. This pipe branches at B into two pipes BC and BD each of $25$ mm diam and a third pipe BE of $50$ mn diam. The flow rates are such that the flow through BC is three times the flow rate through BE and the velocity through BD is $4\frac{m}{s}.$ Find the flow rates in the three branches $BC,BD$ and BE and the velocities in pipes $AB,BC$ and BE $.$

$(9\mathrm{.}77d\frac{m^3}{s},1\mathrm{.}96d\frac{m^3}{s},3\mathrm{.}26d\frac{m^3}{s},1\mathrm{.}91\frac{m}{s},19\mathrm{.}92\frac{m}{s},1\mathrm{.}66\frac{m}{s})$