A cylindrical vessel with internal diameter 10 cm and height 10.5 cm is full of water. A solid cone of base diameter 7 cm and height 6 cm is completely immersed in water. Find the volume of water
(i) displaced out of the cylinder
(ii) left in the cylinder.
We have,
Internal radius of the cylindrical vessel, $R=\frac{10}{2}=5 \mathrm{~cm}$,
Height of the cylindrical vessel, $H=10.5 \mathrm{~cm}$,
Radius of the solid cone, $r=\frac{7}{2}=3.5 \mathrm{~cm}$ and
Height of the solid cone, $h=6 \mathrm{~cm}$
(i)
Volume of water displaced out of the cylinder $=$ Volume of the solid cone
$=\frac{1}{3} \pi r^{2} h$
$=\frac{1}{3} \times \frac{22}{7} \times 3.5 \times 3.5 \times 6$
$=77 \mathrm{~cm}^{3}$
(ii) $\mathrm{As}$,
Volume of the cylindrical vessel $=\pi R^{2} H$
$=\frac{22}{7} \times 5 \times 5 \times 10.5$
$=825 \mathrm{~cm}^{3}$
So, the volume of water left in the cylindrical vessel = Volume of the cylindrical vessel - Volume of the solid cone
$=825-77$
$=748 \mathrm{~cm}^{3}$