Fluid Mechanics with teacher's notes

Chapter 9
Summary
Teaching Tip
Ask students to prepare a concept
map of the chapter. The concept
map should include most of the
vocabulary terms, along with
other integral terms or concepts.
342
KEY TERMS
buoyant force (p. 319)
fluid (p. 318)
ideal fluid (p. 332)
mass density (p. 319)
pressure (p. 325)
temperature (p. 331)
342
Chapter 9
CHAPTER 9
Summary
KEY IDEAS
Section 9-1 Fluids and buoyant force
• A fluid is a material that can flow, and thus it has no definite shape. Both
gases and liquids are fluids.
• Buoyant force is an upward force exerted by a fluid on an object floating
on or submerged in the fluid.
• The magnitude of a buoyant force for a submerged object is determined
by Archimedes’ principle and is equal to the weight of the displaced fluid.
Section 9-2 Fluid pressure and temperature
• Pressure is a measure of how much force is exerted over a given area.
• The pressure in a fluid increases with depth.
Section 9-3 Fluids in motion
• Moving fluids can exhibit laminar (smooth) flow or turbulent flow.
• An ideal fluid is incompressible, nonviscous, and nonturbulent.
• According to the continuity equation, the amount of fluid leaving a pipe
during some time interval equals the amount entering the pipe during
that same time interval.
• According to Bernoulli’s principle, swift-moving fluids exert less pressure
than slower-moving fluids.
Section 9-4 Properties of gases
• An ideal gas obeys the ideal gas law. The ideal gas law relates the volume, pressure,
and temperature of a gas confined to a container.
Variable symbols
Quantities Units Conversions
r density kg/m 3
kilogram per = 10 –3 g/cm 3
meter 3
P pressure Pa pascal = N/m 2
= 10 −5 atm
T temperature K kelvin
°C degrees Celsius = K − 273
k B Boltzmann’s constant J/K joules per kelvin
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