To find out the absolute pressure P inside a pipe through which a fluid of density $\rho$ flows, place
a barometer (a device used to measure atmospheric pressure) and a manometer (an instrument
used to measure and indicate pressure) side by side, both filled with mercury of density $\rho_0$ and
read $H_0$, $H_1$, and $H_2$ (Fig. 1). Compute the pressure on the pipe axis when the fluid is:
a) air, for which $\rho$ is neglibeable with respect to $\rho_0$
b) water, for which $\rho = 10^3 kg/m^3$
Data: $H_0 = 75.65 cm$, $H_1 = 32.45 cm$, $H_2 = 19.25 cm$, $g = 9,805 m/s^2$, $\rho_0 = 13.59 \cdot 10^3 kg/m^3$