8.3 Fluids in Motion

Which of the following statements does not describe an ideal fluid?

• An ideal fluid is incompressible.

• An ideal fluid has internal friction (viscosity).

• The flow of an ideal fluid is always steady.

• The flow of an ideal fluid is always laminar.

Which type of flow best describes a river moving through rocky rapids?

• steady flow

• laminar flow

• turbulent flow

• viscous flow

What are the irregular motions in a flowing fluid called?

• eddy currents

• turbulent currents

• laminar flows

• nonlinear flows

Which of the following statements about an ideal fluid moving through a pipe with changing diameter provides the basis for the continuity equation?

• The density of the fluid remains constant throughout the pipe.

• The mass of the fluid remains constant throughout the pipe.

• The volume of the fluid remains constant throughout the pipe.

• The speed of the fluid remains constant throughout the pipe.

A fluid has a flow rate of 5.0 m³/s as it travels at a speed of 7.5 m/s through a pipe. What is the cross-sectional area of the pipe?

• 3.8 m²

• 1.5 m²

• 0.67 m²

• 0.27 m²

A fluid flows through a pipe whose cross-sectional area changes from 2.00 m² to 0.50 m². If the fluid’s speed in the wide part of the pipe is 3.5 m/s, what is its speed when it moves through the narrow part of the pipe?

• 0.071 m/s

• 0.88 m/s

• 1.1 m/s

• 14 m/s

Which of the following is a correct statement of Bernoulli’s principle?

• The density of a fluid increases as the fluid’s velocity increases.

• The density of a fluid decreases as the fluid’s velocity increases.

• The pressure in a fluid increases as the fluid’s velocity increases.

• The pressure in a fluid decreases as the fluid’s velocity increases.

The speed of fluid flow depends on ________.

• density.

• temperature.

• surface type.

• cross-sectional area.

A(n) ________ is a fluid that has no internal friction or viscosity and is incompressible.

• laminar

• ideal fluid

• turbulent

• linear

A₁v₁ = A₂v₂

(Area x speed in region 1 = area x speed in region 2) is known as the ______________.

• Continuity equation

• Mass flow equation

• Linear flow equation

• Ideal flow equation