Water is filled in a flask up to a height of 20 cm. The bottom of the flask is circular with a radius of 10 cm. If the atmospheric pressure is 1.01 x 10⁵ Pa then the force exerted by water on the bottom is :

The pressure at the surface of the water is equal to the atmospheric pressure, P_o. The pressure at the bottom will be:

$P = P_{o }+ h\rho g$

Where h is the height of the water column, g is the acceleration due to gravity and $\rho$is the density of water.

$\mathrm{P} = 1.01 \mathrm{x} {10}^5 + (0.2)\left(1000\right)\left(10\right)$

$\mathrm{P} = 1.13 \mathrm{x} {10}^5 \mathrm{Pa}$

Pressure is also given by force per unit area.

The area at the bottom= ${\mathrm{\pi R}}^2= 3.14 \mathrm{x} {(0.1)}^2$

Area = 0.0314 m²

The force exerted on the bottom will be: Pressure x Area

$\mathrm{F} = 1.13 \mathrm{x} {10}^5 \mathrm{x} 0.0314 = 3230 \mathrm{N}$