Question

As per the figure given below, find the total pressure at the bottom.
Density of liquid 1 = 13.6 $g/cc$
Density of liquid 2 = 5.4 $g/cc$
Density of liquid 3 = 2.5 $g/cc$

• A. $97.35\text{kPa}$
• B. $123.68\text{kPa}$
• C. $112.28\text{kPa}$
• D. $145.68\text{kPa}$

Answer 1

The correct option is B $123.68\text{kPa}$

Pressure at the bottom will be the sum of pressure applied by different layers of the liquid with different densities
height of liquid 3 = $h_1$ = 50 cm = 0.5 m
height of liquid 2 = $h_2$ = 80 cm = 0.8 m
height of liquid 1 = $h_3$ = 60 cm = 0.6 m
${\rho }_1$ = 13.6 $g/cc$ = $13600kg/m^3$
${\rho }_2$ = 5.4 $g/cc$ = 5400 $kg/m^3$
${\rho }_3$ = 2.5 $g/cc$ = 2500 $kg/m^3$
So applying formula, $P_1+P_2+P_3$ = Total Pressure P
P = $13600\times g\times 0.5+5400\times g\times 0.8+2500\times g\times 0.6$
P = 123676 Pa = 123.68 kPa