ENGR 130 MIDTERM 2 Questions with Detailed Verified Answers

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ENGR 130 MIDTERM 2 Questions with
Detailed Verified Answers

Question:Air is flowing in a pipe with 0.2 m in diameter at an average velocity
of 0.1 m/s. The density of air is 1.754 kg/m3. What is the mass flow rate?

Ans: 0.0055 kg/s

Reason:

m⋅ = ρVavgAc, Ac = πD^2/4

Question: A nozzle is considered to be a steady flow device where a single
stream flows in and out. Steam with a density of 1.91 kg/m³ with an average
velocity of 122 m/s flows into a nozzle. Its inlet area of the nozzle is 104 ×
10^−4 m^2. Determine its mass flow rate at the nozzle outlet.

Ans: 2.42 kg/s

Reason:

m∙in =m∙out =ρVavgA

Question: True or false: Flow work can be expressed in terms of other
properties.

Ans: True

Question: Which of the following energies are part of the total energy of a
flowing fluid?

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Ans: Enthalpy

Kinetic energy

Potential energy

Question: Which of the following statements are true? (Select all that apply.)

Ans: -the steady-flow process is a process during which a fluid flows through a
control volume and does not change with time-during a steady flow process,
boundary work is zero-the steady flow implies that the fluid properties can
change from point to point, but at any point, they remain constant during the
entire process

Question: The volumetric flow rate of water flowing through a pipe is 5 L/s,
and the density of water is 1 kg/L. What is the mass flow rate?

Ans: 5 kg/s

Reason:

Mass flow rate is equal to the product of density and volumetric flow rate.

Question: True or false: In a single-stream, steady flow system, the mass flow
rates for the inlet and outlet must be the same.

Ans: True

Question: Which of the following statements are true? (Select all that apply.)

Ans: -The rate of change of mass within a control volume minus the net flow
rate in and plus the net flow rate out of the control surface must equal to zero.

-In a steady flow process, the total rate of mass entering a control volume is
equal to the total rate of mass leaving it.

Question: In an open system, when mass flows across control volume
boundaries, some work is required to push the mass into or out of the control
volume, and this is known as ______ work.

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Ans: flow

Question: In a steady flow process, energy can be transferred by ______.

Ans: work, mass, and heat

Question: True or false: The total energy for a flowing fluid consists of an
additional term when compared with the total energy for a nonflowing fluid.
True false question.

Ans: True

Question: During a steady-flow process, the fluid properties at an inlet or exit
must ______.

Ans: remain constant

Question: Nozzle
matches
Choice, A device that increases the velocity of a fluid at the expense of
pressure
A device that increases the velocity of a fluid at the expense of pressure
Diffuser
matches
Choice, A device that increases the pressure of a fluid by slowing it down
A device that increases the pressure of a fluid by slowing it down

Ans: hi

Question: In a single-stream, steady flow system, the mass flow rate can be
defined as the product of ___________, __________, and ___________.

Ans: Density, velocity, and area

Question: Turbine

Ans: produces shaft work

Question: Fan