Hydrostatic Pressure: Example Problems

Try to solve these problems before watching the solutions in the screencasts.

Example Problem 1

A mercury barometer and a water barometer are sitting side by side at the top of Mt. Elbert.  Calculate the height of fluid (in mm) in the barometers, and the ratio of height of the water to height of mercury.  Given the specific weight of mercury is 133.7 kN/m3, the specific weight of water is 9.81 kN/m3, and pressure at the summit is 57.2 kPa. Assume the vapor pressure of mercury is negligible, and the vapor pressure of water is 2.34 kPa. 

 

Example Problem 2

An airplane is flying steadily at 40,000 ft above sea level. Determine the air pressure at this elevation for three cases. 
1) Incompressible
2) Compressible isothermal
3) Compressible non-isothermal.
Assume the specific weight of air is 12.014 N/m3 and the pressure at sea level is 101.33 kPa.