Problem $3\mathrm{.}40$: Determine:

$($a$)$ the difference in pressure and $($b$)$ the difference in piezometric head between points A and B $.$ The elevations $z_A$ and $z_R$ are $10$ m and $11$ m $,$ respectively, $l_{1}1m,$ and the manometer deflection $l_1$ is $50$ cm $.$

Problem $3\mathrm{.}50$: Denver, Colorado, is called the "mile$-$high" city. What are the pressure, temperature, and density of the air when standard atmospheric conditions prevail? Give your answer in traditional and SI units.