Energy Equation: Master Fluid Dynamics with Interactive Quizzes

Question 1

Which of the following assumptions is NOT made in the derivation of the energy equation?

Accepted Answer

No mechanical energy loss

Answer

Steady flow

Answer

Uniform flow

Answer

Incompressible flow

Question 2

Consider a fluid flowing through a pipe of varying cross-sectional area. Which term in the energy equation represents the change in pressure energy per unit mass?

Accepted Answer

pv

Answer

-gh

Answer

v^2/2

Answer

gz

Question 3

Consider a fluid flowing through a Venturi tube. Which of the following statements about the energy equation is correct?

Accepted Answer

The pressure energy increases as the velocity energy decreases.

Answer

The total energy remains constant throughout the tube.

Answer

The potential energy remains constant throughout the tube.

Answer

The velocity energy increases as the pressure energy decreases.

Question 4

Which of the following devices converts mechanical energy into fluid energy?

Accepted Answer

Pump

Answer

Turbine

Answer

Valve

Answer

Filter

Question 5

Which of the following losses are considered in the energy equation for flow through a pipe:

Accepted Answer

Both friction and minor losses

Answer

Friction

Answer

Minor losses

Answer

Heat transfer

Question 6

Compared to the energy equation for incompressible fluids, the energy equation for compressible fluids includes an additional term for:

Accepted Answer

Internal energy

Answer

Potential energy

Answer

Kinetic energy

Answer

Pressure energy

Question 7

True or False: The energy equation can be used to directly derive the Bernoulli equation for inviscid, incompressible flow.

Accepted Answer

True

Answer

False

Question 8

In the energy equation for flow through a turbine, the term 'work done' represents:

Accepted Answer

Power generated by the turbine

Answer

Head loss across the turbine

Answer

Kinetic energy of the fluid leaving the turbine

Answer

Internal energy change of the fluid

Question 9

Enhanced: Bernoulli's equation is derived from the conservation of:

Accepted Answer

Energy

Answer

Mass

Answer

Momentum

Answer

Mass and momentum

Question 10

Enhanced: Which of the following is NOT an assumption made when deriving the energy equation for incompressible fluids?

Accepted Answer

Adiabatic flow

Answer

Steady flow

Answer

Negligible viscous effects

Answer

Uniform velocity distribution

Question 11

Enhanced: How does friction affect the energy equation in a pipe flow system?

Accepted Answer

Decreases the total head

Answer

Increases the total head

Answer

Has no effect on the total head

Answer

Changes the sign of the total head

Question 12

Enhanced: What is the dimensional homogeneity check for the energy equation, ensuring proper units and dimensions?

Accepted Answer

Length

Answer

Time

Answer

Force

Answer

Acceleration

Question 13

Question: Which of the following is NOT a form of mechanical energy associated with fluid flow?

Accepted Answer

Option D: Electrical energy

Answer

Option A: Potential energy

Answer

Option B: Kinetic energy

Answer

Option C: Internal energy

Question 14

Question: Which of the following factors does NOT affect the head developed by a pump?

Accepted Answer

Option D: Temperature of the fluid

Answer

Option A: Pump speed

Answer

Option B: Pump impeller diameter

Answer

Option C: Fluid density

Question 15

Question: The energy equation can be used to analyze flow through a converging-diverging nozzle by considering:

Accepted Answer

Option D: All of the above

Answer

Option A: Area change

Answer

Option B: Velocity change

Answer

Option C: Pressure change

Question 16

In the energy equation, which device is employed to measure pressure?

Accepted Answer

Manometer

Answer

Hot-wire anemometer

Answer

Laser Doppler velocimetry

Question 17

In the derivation of the energy equation for incompressible fluid flow, which term is essential?

Accepted Answer

Pressure gradient

Answer

Velocity gradient

Answer

Temperature gradient

Question 18

In fluid mechanics, which equation is specifically used to analyze pressure changes caused by elevation differences?

Accepted Answer

Bernoulli's equation

Answer

Pump performance analysis

Answer

Turbine efficiency evaluation

Answer

Flow characteristics in pipes

Question 19

Which term in the energy equation explicitly represents the change in internal energy of a fluid?

Accepted Answer

dE

Answer

dv

Answer

dh

Answer

dp

Question 20

The energy equation for a steady flow system encompasses which of the following quantities?

Accepted Answer

Pressure, velocity, and elevation

Answer

Temperature, volume, and viscosity

Answer

Density, specific heat, and mass flow rate

Answer

Entropy, enthalpy, and exergy

Question 21

In the energy equation applied to a pump, which term denotes the work done by the pump?

Accepted Answer

+W_p

Answer

-W_p

Answer

-Q

Answer

+Q

Question 22

When applying the energy equation to flow through a pipe, which assumptions are typically made?

Accepted Answer

Steady, incompressible, and frictionless flow

Answer

Laminar, viscous, and adiabatic flow

Answer

Unsteady, compressible, and turbulent flow

Answer

Isothermal, reversible, and inviscid flow

Question 23

The Bernoulli equation, a simplified form of the energy equation, applies specifically to:

Accepted Answer

Inviscid, irrotational flow

Answer

Turbulent, unsteady flow

Answer

Laminar, steady flow

Answer

Viscous, compressible flow

Question 24

The Moody diagram is primarily used to determine:

Accepted Answer

Friction factor

Answer

Velocity profile

Answer

Reynolds number

Answer

Pipe roughness

Question 25

Which flow regime results in the highest head loss?

Accepted Answer

Turbulent flow

Answer

Laminar flow

Answer

Transitional flow

Answer

Stokes flow

Question 26

A limitation of the energy equation is that it:

Accepted Answer

Assumes steady, one-dimensional flow

Answer

Can predict pressure drop in complex geometries

Answer

Can be applied to all types of fluids

Answer

Accounts for viscous effects

Question 27

Which type of energy loss is represented by 'hl' in the energy equation?

Accepted Answer

Friction loss

Answer

Minor loss

Answer

Exit loss

Answer

Gravity loss

Question 28

Which of the following is a simplifying assumption made when deriving the energy equation for an incompressible flow?

Accepted Answer

Density remains constant

Answer

Acceleration is negligible

Answer

Velocity is constant

Answer

Pressure is constant

Question 29

What is the Bernoulli equation?

Accepted Answer

A special case of the energy equation, applicable to incompressible, irrotational, and inviscid flows

Answer

An equation used to determine the magnitude of fluid velocity

Answer

An equation used to predict the direction of fluid flow

Question 30

To which flow conditions is the energy equation not applicable?

Accepted Answer

Unsteady flows

Answer

Laminar flows

Answer

Turbulent flows

Answer

Steady flows

Question 31

What is the primary significance of the energy equation in fluid mechanics?

Accepted Answer

It provides a tool for analyzing and designing fluid flow systems by relating pressure, velocity, and elevation at different points

Answer

It determines the magnitude of fluid velocity

Answer

It predicts the direction of fluid flow

Question 32

What is the primary purpose of using the energy equation in fluid mechanics?

Accepted Answer

To determine the pressure, velocity, and elevation at different points in a flow system

Answer

To calculate the friction factor of a pipe

Answer

To predict the cavitation potential of a fluid

Question 33

A pump adds 100 J of energy to a fluid per unit mass. If the fluid's initial velocity is 2 m/s and its final velocity is 5 m/s, what is the change in pressure head (in meters of fluid) caused by the pump?

Accepted Answer

14.25 m

Answer

28.5 m

Answer

20.25 m

Answer

10.5 m

Question 34

A fluid flows through a pipe with a diameter of 10 cm and a velocity of 2 m/s. The pipe then reduces to a diameter of 5 cm. Assuming incompressible flow, what is the velocity of the fluid in the smaller pipe?

Accepted Answer

8 m/s

Answer

2 m/s

Answer

4 m/s

Answer

16 m/s

Question 35

A turbine extracts 50 kW of power from a fluid flow. If the fluid's mass flow rate is 10 kg/s and its inlet velocity is 10 m/s, what is the fluid's exit velocity (in m/s)?

Accepted Answer

5 m/s

Answer

10 m/s

Answer

15 m/s

Answer

20 m/s

Question 36

Which of the following terms is NOT included in the general energy equation?

Accepted Answer

Entropy change

Answer

Work done by external forces

Answer

Kinetic energy change

Answer

Potential energy change

Question 37

A fluid flows through a horizontal pipe with a head loss of 10 m. What is the change in pressure (in kPa) due to this head loss, considering a fluid density of 1000 kg/m³?

Accepted Answer

98 kPa

Answer

49 kPa

Answer

10 kPa

Answer

196 kPa

Question 38

The Bernoulli's equation is a simplified form of the energy equation that assumes:

Accepted Answer

Incompressible and inviscid flow

Answer

Steady and unsteady flow

Answer

Compressible and viscous flow

Answer

Irrotational and rotational flow

Question 39

A fluid flows through a pipe with a diameter of 20 cm and a velocity of 3 m/s. What is the volumetric flow rate (in m³/s)?

Accepted Answer

0.0942 m³/s

Answer

0.1885 m³/s

Answer

0.0377 m³/s

Answer

0.377 m³/s

Question 40

The energy equation is based on the principle of:

Accepted Answer

Conservation of energy

Answer

Conservation of mass

Answer

Conservation of momentum

Answer

Conservation of angular momentum

Question 41

Which of the following factors can cause head loss in a pipe flow?

Accepted Answer

Friction between the fluid and pipe walls

Answer

Increase in fluid velocity

Answer

Increase in fluid pressure

Answer

Decrease in fluid density

Question 42

The energy equation can be used to analyze the performance of which of the following devices?

Accepted Answer

Pumps, turbines, and valves

Answer

Only pumps and turbines

Answer

Only pumps and valves

Question 43

Which term in the energy equation accounts for energy losses due to friction and turbulence?

Accepted Answer

Head loss

Answer

Velocity head

Answer

Elevation head

Question 44

In a pump, the energy equation is used to determine:

Accepted Answer

Head added to the fluid

Answer

Power required to operate the pump

Answer

Efficiency of the pump

Answer

Flow rate through the pump

Question 45

The energy equation can be expressed in various forms, which of the following is NOT a valid form?

Accepted Answer

Bernoulli's equation + Darcy-Weisbach equation

Answer

Navier-Stokes equation

Answer

Hagen-Poiseuille equation

Answer

Euler's equation

Question 46

In a pipe flow, which term in the energy equation represents the kinetic energy of the fluid?

Accepted Answer

Velocity head

Answer

Friction head

Answer

Elevation head

Answer

Pressure head

Question 47

The energy equation is a differential equation, what does this imply?

Accepted Answer

It describes how the energy changes continuously along a streamline.

Answer

It assumes steady-state flow.

Answer

It can only be applied to incompressible fluids.

Question 48

Which of the following assumptions is made when deriving the energy equation?

Accepted Answer

Inviscid flow

Answer

Incompressible flow

Answer

Steady-state flow

Answer

Laminar flow

Question 49

In a converging nozzle, the energy equation predicts:

Accepted Answer

An increase in velocity and a decrease in pressure

Answer

Constant velocity and constant pressure

Answer

A decrease in velocity and an increase in pressure

Question 50

Which of the following is a limitation of the energy equation?

Accepted Answer

It does not account for heat transfer

Answer

It can be applied to unsteady flows

Answer

It is accurate for both high and low Reynolds numbers

Answer

It is valid for all fluids

Question 51

The energy equation is often used in conjunction with which other equation to analyze fluid flow?

Accepted Answer

Continuity equation

Answer

Momentum equation

Answer

Bernoulli's equation

Answer

Navier-Stokes equations

Question 52

Which term in the energy equation represents the work done by a pump or turbine?

Accepted Answer

Shaft work

Answer

Gravitational work

Answer

Pressure work