Question

A tank is filled with water of density ${10}^{3}kg/m^3$ and oil of density $9\times {10}^{3}kg/m^3$. The height of water layer is $1m$ and that of the oil layer is $4m$. The velocity of efflux from an opening in the bottom of the tank is:

• A. $\sqrt{85}m/s$
• B. $\sqrt{88}m/s$
• C. $\sqrt{82}m/s$
• D. $\sqrt{98}m/s$

Answer 1

The correct option is C $\sqrt{82}m/s$

Now applying bernaulis equation on points $A$ and $B$ we get.

$Po+O+O=P_0+\frac{1}{2}{\rho }_0{V}^2[{\rho }_{w}g\left(1\right)+{\rho }_{0}g\left(4\right)]$

$\Rightarrow \frac{1}{2}(9\times {10}^3)V^2={10}^4+36\times {10}^4$

$\Rightarrow V=\sqrt{\frac{370\times 2}{9}}$

$\Rightarrow V=\sqrt{82.2}m/s$