Unit 27: Pressure & Manometers

Practice Problems

Note: problem difficulty is ranked using a star system.

  • (*) One-star problems are fundamental to the unit, and can be done relatively quickly. Use these problems to introduce yourself to the material.

  • (**) Two-star problems are more difficult, and require an understanding of one or two key concepts. Use these problems to test your understanding of the material.

  • (***) Three-star problems are the most difficult, and require some creative thinking in addition to a deep familiarity with multiple key concepts. Use these problems to challenge yourself; if you can complete one of these, you’re on your way to mastering the material.

*Q27.1) Convert 1.5 atm of pressure to the following units:

a) Pascals

b) Kilopascals

c) Bar

d) Psi

e) mmHg

*Q27.2) Describe the difference between an absolute pressure and a gauge pressure. What’s the absolute pressure of the atmosphere at sea level? What’s the gauge pressure of the atmosphere at sea level? If a gas is pressurized to 180 kPa of absolute pressure, what’s the gauge pressure of the gas (in kPa)?

*Q27.3) How deep below the surface of the ocean would you have to dive for the absolute pressure to reach twice that of the surface?

**Q27.4) Determine the unknown gas pressure (both gauge and absolute) using the manometer shown below:

**Q27.5) Two manometers are connected to a container of pressurized gas as shown below. Determine the density of the unknown liquid in the manometer on the right.

***Q27.6) A manometer contains three immiscible liquids as shown below. Determine the pressure difference P₁ - P₂.