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Noise & Vibration Control MCQ

1. What is the definition of Probabilistic Vibration?

Vibration with a magnitude that can only be predicted on a statistical basis.

Vibration with a magnitude that can be predicted on a mathematical basis.

Vibration with a magnitude that can be predicted on a deterministic basis.

Vibration with a magnitude that can be predicted on an intuitive basis.

Answer

Correct Answer: Vibration with a magnitude that can only be predicted on a statistical basis.

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2. What is the magnitude of probabilistic vibration?

Cannot be predicted on a statistical basis

All of the above

On a statistical basis

Deterministic vibration

Answer

Correct Answer: Cannot be predicted on a statistical basis

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3. What is the meaning of "platform" in MIL-STD-810?

A structure that is used to support equipment.

A foundation that is used to hold equipment in place.

Any vehicle, surface, or medium that carries a piece of equipment.

A device that is used to store or mount equipment.

Answer

Correct Answer: Any vehicle, surface, or medium that carries a piece of equipment.

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4. What is a platform?

A type of vehicle

A raised area

A surface on which something stands

Any vehicle, surface, or medium that carries a piece of equipment

Answer

Correct Answer: Any vehicle, surface, or medium that carries a piece of equipment

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5. What is a piezoresistive transducer?

A transducer with apiezoelectric output that depends on the deformation of its semiconductor resistive element

A transducer with an electrical output that depends on the deformation of its semiconductor resistive element

A transducer with a mechanical output that depends on the deformation of its semiconductor resistive element

A transducer with an electrical output that does not depend on the deformation of its semiconductor resistive element

Answer

Correct Answer: A transducer with an electrical output that depends on the deformation of its semiconductor resistive element

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6. Which of the following is true about a piezoresistive transducer?

It is not as sensitive as a strain-gauge transducer.

It offers greater resistance to change than the wire of a strain-gauge transducer for a given deformation.

It does not have an electrical output that depends on the deformation of its semiconductor resistive element.

Its semiconductor resistive element does not deform.

Answer

Correct Answer: It offers greater resistance to change than the wire of a strain-gauge transducer for a given deformation.

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7. What is the fractional part of a period called?

Phase

Wavelength

Magnitude

Amplitude

Answer

Correct Answer: Phase

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8. Which of the following is a characteristic of performance-based requirements?

They describe the environment in which the product should operate.

They describe how the product should perform.

They describe how the product should be designed.

They describe what the product should do.

Answer

Correct Answer: They describe what the product should do.

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9. What is a patent defect?

A flaw in and/or the workmanship of a part or assembly that has failed under a test or screen.

A legal designation for a physical or mental disability that affects the ability to earn a living.

A screen or test for latent defects.

A physical or mental disability that affects the ability to earn a living.

Answer

Correct Answer: A flaw in and/or the workmanship of a part or assembly that has failed under a test or screen.

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10. What is an orbit?

The path of a celestial object around another object

A movement of the Earth around the Sun

The path of a shaft centerline during rotation

The path of a satellite around a planet

Answer

Correct Answer: The path of a shaft centerline during rotation

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11. What is a precomputed drive signal in open-loop control?

A signal that is refined based on observation of the resulting motion.

A signal that is modified based on observation of the resulting motion.

A signal that is computed before it is sent to the system.

A signal that is sent to the system without being computed first.

Answer

Correct Answer: A signal that is computed before it is sent to the system.

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12. What is Open-loop control?

Precomputed or preconceived drive signals without modifying or refining the signals based on observation of the resulting motion.

Modifying or refining the signals based on observation of the resulting motion.

Preconceived drive signals

Closed loop

Answer

Correct Answer: Precomputed or preconceived drive signals without modifying or refining the signals based on observation of the resulting motion.

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13. What is the control of a computer's data sampling rate called?

Data sampling

Data interpretation

Data analysis

Order tracking

Answer

Correct Answer: Order tracking

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14. What does operational limit refer to?

The extremes beyond which a product is not expected to operate.

The amount of money a company is willing to spend on product development.

The life expectancy of a product.

The number of units of a product that a company is willing to produce.

Answer

Correct Answer: The extremes beyond which a product is not expected to operate.

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15. What is an octave?

The interval between two frequencies differing by exactly 2:1

The smallest unit of sound in music

The highest note that a person can sing

The lowest note on a piano

Answer

Correct Answer: The interval between two frequencies differing by exactly 2:1

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16. What is the interval between two frequencies differing by exactly 2:1 called?

Hertz

Decibel

Yamaha

Octave

Answer

Correct Answer: Octave

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17. What is the definition for nonlinearity?

The deviation from a straight line of the true output versus the actual value measured.

A best fit straight line of the true output versus the actual value measured.

The deviation from a best fit straight line of the true output versus the actual value measured.

The deviation from a best fit straight line of the true output.

Answer

Correct Answer: The deviation from a best fit straight line of the true output versus the actual value measured.

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18. What is an undamped system's natural frequency also known as?

The frequency of an damped system's free vibration.

The frequency of an system's forced vibration.

The frequency of an system's free vibration.

The frequency of the normal modes of vibration.

Answer

Correct Answer: The frequency of the normal modes of vibration.

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19. What is the natural frequency of an undamped system's free vibration?

It is the reciprocal of the frequency of the system's normal modes of vibration.

It is twice the frequency of the system's normal modes of vibration.

It is the square root of the frequency of the system's normal modes of vibration.

It is the frequency of the system's normal modes of vibration.

Answer

Correct Answer: It is the frequency of the system's normal modes of vibration.

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20. What is the purpose of notching?

To limit the peak vibrations in the notched area

To prevent unnecessary excitation of any large resonances that may occur during a vibration test.

To remove frequencies from the spectrum

To add frequencies to the spectrum

Answer

Correct Answer: To prevent unnecessary excitation of any large resonances that may occur during a vibration test.

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21. What is the noise floor?

The signal-to-noise ratio.

The summation of all noise sources and unwanted signals within a measurement system.

The highest frequency that can be measured.

The lowest frequency that can be measured.

Answer

Correct Answer: The summation of all noise sources and unwanted signals within a measurement system.

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22. What is the definition of natural environment?

Environments that are not suitable for human life

Environments that are caused by humans

Environments that are only found in nature

Conditions that occur in nature and are not caused by equipment

Answer

Correct Answer: Conditions that occur in nature and are not caused by equipment

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23. What is a mission profile?

Description of the events and environments an item experiences from initiation to completion of a specified mission

Time-based description of the events and environments an item experiences from initiation to completion of a specified mission

Time-phased description of the events and environments an item experiences from initiation to completion of a specified mission.

Time-phased description of the events and environments an item experiences from initiation to completion of a specified mission

Answer

Correct Answer: Time-phased description of the events and environments an item experiences from initiation to completion of a specified mission.

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24. One micron is equal to _______.

10-3 meters

1/1000 meter

10-6 meters

10-9 meters

Answer

Correct Answer: 10-6 meters

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25. How many microns are in one inch?

1000

1000000

254000

Answer

Correct Answer: 254000

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26. What is mechanical failure?

A machine that helps motors work

A machine that helps people move

A malfunction consisting of cracking, excessive displacement, misalignment, loosening, etc.

A device that helps machines run

Answer

Correct Answer: A malfunction consisting of cracking, excessive displacement, misalignment, loosening, etc.

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27. What is the mean?

The average of all the numbers in a set

A value intermediate between quantities under consideration

The sum of all the numbers in a set

The most common value in a set

Answer

Correct Answer: A value intermediate between quantities under consideration

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28. What is Machinery health monitoring?

The measurement, recording, and analysis of machinery parameters to determine machinery health.

The study of human health

The study of animal health

The study of plant health

Answer

Correct Answer: The measurement, recording, and analysis of machinery parameters to determine machinery health.

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29. What is the other name for lateral sensitivity?

Linear sensitivity

Cross-axis sensitivity

Longitudinal sensitivity

Angular sensitivity

Answer

Correct Answer: Cross-axis sensitivity

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30. What is Lateral sensitivity?

Direction of a sensor perpendicular to the sensitive axis.

A measure of how much a sensor's output changes when the target is moved a small distance laterally.

Sensitivity of a sensor in a direction perpendicular to the sensitive axis.

The ability of a sensor to detect changes in direction.

Answer

Correct Answer: Sensitivity of a sensor in a direction perpendicular to the sensitive axis.

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31. What is liquid nitrogen's chemical formula?

LN2

NH3

NO2

N2O6

Answer

Correct Answer: LN2

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32. What is a life unit?

A unit of measurement for time

A unit of measurement for distance

A measurement of an item's use duration

A unit of measurement for weight

Answer

Correct Answer: A measurement of an item's use duration

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33. What does the life unit measurement include?

The location of the item

Time, cycles, distance, rounds fired, attempts to operate, etc.

When the item was made

The amount of money an item is worth

Answer

Correct Answer: Time, cycles, distance, rounds fired, attempts to operate, etc.

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34. The logarithm is normally base ____.

Answer

Correct Answer: 10

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35. What is a latent defect?

A flaw in a part, assembly, and/or workmanship that is dormant but can result in failure.

A flaw in a part, assembly, and/or workmanship that is immediately apparent visually or by electrical test.

Answer

Correct Answer: A flaw in a part, assembly, and/or workmanship that is dormant but can result in failure.

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36. What is a keyphasor?

A machine that helps alleviate back pain

A signal generated by a sensor that observes a once-per-revolution event

A device used to measure pressure

A type of electrical connector

Answer

Correct Answer: A signal generated by a sensor that observes a once-per-revolution event

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37. What is the rate of change of acceleration with time called?

Velocity

Acceleration

Jerk

Force

Answer

Correct Answer: Jerk

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38. What does intensity measure?

The severity of vibration or shock

The amount of wave passing a point

Frequency of sound wave

The loudness of sound

Answer

Correct Answer: The severity of vibration or shock

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39. What is the input impedance?

Series resistance and capacitance/inductance measured at the input terminals

Shunt resistance and capacitance/inductance measured at the input terminals

Series resistance and capacitance/inductance measured at the output terminals

Shunt resistance and capacitance/inductance measured at the output terminals

Answer

Correct Answer: Shunt resistance and capacitance/inductance measured at the input terminals

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40. What is another term for "inertially-referenced motion"?

Free space

Relative motion

Fixed point

Motionless

Answer

Correct Answer: Free space

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41. A sensor that measures motion referenced to a fixed point in space is what?

Inertially-referenced

Motionless

66.6 m/s

.5 m/s

Answer

Correct Answer: Inertially-referenced

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42. What is an impulse?

The integral of force over a time interval.

The average of force over a time interval.

Force multiplied by time.

The sum of force over a time interval.

Answer

Correct Answer: The integral of force over a time interval.

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43. What is the cause of imbalance?

The unequal distribution of weight or mass on a rotor

The geometric center of the mass is along the shaft centerline

The rotor is not mounted on the shaft correctly

There is too much weight on one side of the rotor

Answer

Correct Answer: The unequal distribution of weight or mass on a rotor

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44. What is the unequal distribution of weight or mass on a rotor called?

Unsteadiness

Wobble

Malformation

Imbalance

Answer

Correct Answer: Imbalance

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45. What is hash?

A cryptographic function

A distortion in a signal

A programming language

A type of weed

Answer

Correct Answer: A distortion in a signal

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46. What is a hard failure?

When a product under test works correctly but does not resume correct operation when the stress environment is eased.

When a product under test works correctly but does not resume correct operation when the stress environment is increased.

When a product under test ceases to work correctly but resumes correct operation when the stress environment is eased.

When a product under test ceases to work correctly and does not resume correct operation.

Answer

Correct Answer: When a product under test ceases to work correctly and does not resume correct operation.

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47. What does a haversine pulse look like?

An inverted sine wave

A rounded transition

A sine wave

A cosine offset by half its amplitude

Answer

Correct Answer: A sine wave

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48. What is harmonic distortion?

A type of fraud

A programming language

A distortion in an output signal caused by the presence of frequencies not present in the input signal

The study of how humans interact with machines

Answer

Correct Answer: A distortion in an output signal caused by the presence of frequencies not present in the input signal

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49. What does HALT stand for?

High Anxiety Life Test

High Amount Life Test

Highly Accelerated Life Test

High Altitude Life Test

Answer

Correct Answer: Highly Accelerated Life Test

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50. What does the acronym HALT stand for?

Highly accelerated life tests

Highly active long-term

Homeostatic anxiety level tests

High altitude long-term

Answer

Correct Answer: Highly accelerated life tests

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51. What is the value for 1 gravitational unit?

8.80665 m/s²

9.80665 m/s²

10.80665 m/s²

9.70665 m/s²

Answer

Correct Answer: 9.80665 m/s²

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52. How many gals are equivalent to 1g?

250

400

980.6

1000

Answer

Correct Answer: 980.6

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53. What is the acceleration represented by the unit gal?

1 cm/sec²

1 m/sec²

1 km/sec²

1 ft/sec²

Answer

Correct Answer: 1 cm/sec²

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54. What is the main cause of a ground loop?

Voltage drops between the two ground connections

Signal source and measurement device are not grounded

Lack of currentflow

Two ground points on a ground bus

Answer

Correct Answer: Voltage drops between the two ground connections

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55. What are ground loops caused by?

A signal source and a signal measurement device being grounded at two separate points on a ground bus.

Two signal sources being grounded at the same point.

A signal source and a ground being connected at two separate points.

A signal source and a measurement device being connected at two separate points.

Answer

Correct Answer: A signal source and a signal measurement device being grounded at two separate points on a ground bus.

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56. What does graduation mark mean?

A line on a graduated cylinder

The peak of a hill or mountain

The scale intervals on a measuring instrument

A ceremony in which students receive academic degrees

Answer

Correct Answer: The scale intervals on a measuring instrument

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57. What does the PSD measure?

The signal is measured in length using the metric system.

The signal is measured in acceleration using the gravitational constant G.

The signal is measured in weight using the gravitational constant G.

The signal is measured in time using the metric system.

Answer

Correct Answer: The signal is measured in acceleration using the gravitational constant G.

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58. What are the units of PSD?

G/Hz

G2/Hz

M2/Hz

Answer

Correct Answer: G2/Hz

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59. What is FEA?

A mathematical technique for solving problems in physics

A computer-aided design technique for predicting the dynamic behavior of a mechanical system.

A computer-aided design technique for predicting the static behavior of a mechanical system.

A graphical technique for solving problems in chemistry

Answer

Correct Answer: A computer-aided design technique for predicting the dynamic behavior of a mechanical system.

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60. What does the definition of MTBF stand for?

Modulating Transfer Function

Minimum Trouble Before Fracture

Mean Time Between Failures

Many Thanks Brand Fans

Answer

Correct Answer: Mean Time Between Failures

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61. What is the definition of failure?

Failure is the event or inoperable state in which any item or component does not perform as previously specified.

The event or state in which an item or component meets or exceeds its performance specifications.

The event or state in which an item or component performs as expected.

The event or state in which an item or component has surpassed its performance specifications.

Answer

Correct Answer: Failure is the event or inoperable state in which any item or component does not perform as previously specified.

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62. What is the goal of environmental stress screening?

Eliminate all possible defects

Raise the stress levels of all potential failures

Increase product reliability

Precipitate latent defects into recognizable failures

Answer

Correct Answer: Precipitate latent defects into recognizable failures

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63. When is an eddy current generated?

When an inductor is placed in a magnetic field

When a capacitor is placed in an electric field

When a conductor is placed in a magnetic field

When a conductive material intercepts the electromagnetic field of a displacement or proximity probe

Answer

Correct Answer: When a conductive material intercepts the electromagnetic field of a displacement or proximity probe

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64. What are equal loudness curves?

A type of graph

A way of measuring loudness

A unit of sound

Graphs of pure tone sound pressure levels versus frequency.

Answer

Correct Answer: Graphs of pure tone sound pressure levels versus frequency.

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65. What is the meaning of the word "environment"?

The aggregate of all external and internal conditions that influence the form, performance, reliability, or survival of an item.

A home or environment in which someone or something develops

The protection or improvement of the natural surroundings

The study of the interactions of living organisms and their physical and chemical surroundings

Answer

Correct Answer: The aggregate of all external and internal conditions that influence the form, performance, reliability, or survival of an item.

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66. What is environment defined as?

An aggregate of all external and internal conditions that influence the form, performance, reliability, or survival of an item.

A measure of the average kinetic energy of particles in a system.

The settings in which a particular situation is set.

A set of surrounding conditions or elements.

Answer

Correct Answer: An aggregate of all external and internal conditions that influence the form, performance, reliability, or survival of an item.

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67. What is mechanical eccentricity?

A variation of the shaft surface radius when referenced to the shaft’s true geometric centerline.

The amount of slippage between two interconnected gears

A machine that uses gears to transfer motion and force from one place to another

A change in the speed of a rotating object

Answer

Correct Answer: A variation of the shaft surface radius when referenced to the shaft’s true geometric centerline.

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68. What is distortion in electronics?

Any signal that is not clean

Any signal that is not intended to be amplified

Any unwanted signal

Any signal that is not amplified

Answer

Correct Answer: Any unwanted signal

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69. In which field is distortion defined as any unwanted signal?

Biology

Mechanics

Electronics

Chemistry

Answer

Correct Answer: Electronics

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70. What is accomplished by multiplying the velocity signal by jΩ in a computer?

Amplification of the signal

None of the above

Representation in terms of time rate of change.

Representation of time as a linear function

Answer

Correct Answer: Representation in terms of time rate of change.

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71. What does differentiating velocity yields?

Velocity

Acceleration

Representation

Time

Answer

Correct Answer: Acceleration

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72. What is the number of DOF?

The number of values in the final calculation of a statistic that are free to vary.

The number of values in the final calculation of a statistic.

Answer

Correct Answer: The number of values in the final calculation of a statistic that are free to vary.

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73. What is the number of directions of motion on a structure?

Frequency

Degrees of freedom

Power spectral density

Random vibration testing

Answer

Correct Answer: Degrees of freedom

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74. What is the main purpose of damping?

To dissipate oscillatory or vibratory energy

To shift the phase of oscillations

To reduce the amplitude of oscillations

To increase the amplitude of oscillations

Answer

Correct Answer: To dissipate oscillatory or vibratory energy

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75. What is the definition of damping?

A sudden release of energy

The transfer of energy from one object to another

The increase of kinetic energy

The dissipation of oscillatory or vibratory energy with motion or with time.

Answer

Correct Answer: The dissipation of oscillatory or vibratory energy with motion or with time.

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76. What is a digital-to-analog converter?

A device that converts a digital signal into an audio signal

A device that converts an analog signal into a digital signal

A device that converts a digital signal into an analog voltage

A device that increases the voltage of a digital signal

Answer

Correct Answer: A device that converts a digital signal into an analog voltage

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77. What is the reciprocal of stiffness?

Modulus of elasticity

Bulk modulus

Compliance

Young's modulus

Answer

Correct Answer: Compliance

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78. What does compliance describe?

Reciprocal of stiffness

Force divided by displacement

Product of stiffness and displacement

Displacement divided by force

Answer

Correct Answer: Displacement divided by force

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79. What is the purpose of closed-loop control?

To send drive signals to a control system.

To refine or modify drive signals to bring responses closer to desired motions.

To measure responses and send them back to a control system.

To open and close a loop in a control system.

Answer

Correct Answer: To refine or modify drive signals to bring responses closer to desired motions.

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80. What is chatter?

A sound made by a machine

A unit of measure for sound

An event that can occur in response to shock vibration

A mechanical device that amplifies sound

Answer

Correct Answer: An event that can occur in response to shock vibration

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81. What is a sensor?

A device that uses electrical signals to control physical devices

A device that converts a physical quantity, such as light intensity or pressure, into an electrical signal

A device that amplifies electrical signals

A device that converts electrical signals into physical signals

Answer

Correct Answer: A device that converts a physical quantity, such as light intensity or pressure, into an electrical signal

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82. What does calibration mean?

A method of increasing the accuracy of measurements

The process of determining sensitivity as a function of frequency, temperature, altitude, etc.

A way of adjusting devices to get more precise readings

The process of adjusting the measured voltage and frequency readings based on a precise internal reference voltage.

Answer

Correct Answer: The process of adjusting the measured voltage and frequency readings based on a precise internal reference voltage.

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83. What is the primary purpose of a barrier?

To improve fuel economy

To protect passengers in a crash

To absorb vibrations

To block airborne sound from entering the passenger compartment

Answer

Correct Answer: To block airborne sound from entering the passenger compartment

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84. What is the purpose of a bounce test?

To measure the level of impurities in a sample

To assess the effect of vibration on unrestrained cargo

To determine the amount of force required to break a material

To calculate the density of a substance

Answer

Correct Answer: To assess the effect of vibration on unrestrained cargo

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85. What does bias refer to?

A more or less persistent tendency for a group of measurements to be too large or too small.

The process of collecting data

The process of analyzing data

Large group of people with a common interest

Answer

Correct Answer: A more or less persistent tendency for a group of measurements to be too large or too small.

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86. What is the unit of measurement for bandwidth?

Bps

GBps

MBps

Answer

Correct Answer: Hz

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87. What is a sound exemplified by loose power transformer laminations?

Hiss

Whining

Hum

Roar

Answer

Correct Answer: Hum

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88. What is the power frequency in Hz of a sound exemplified by loose power transformer laminations?

Answer

Correct Answer: 60

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89. What is the definition of broadband?

A high-speed Internet connection

The amount of data transmitted in a given amount of time

A measure of how much data can be sent over a connection in a given amount of time.

Vibration or other signals that are unfiltered.

Answer

Correct Answer: Vibration or other signals that are unfiltered.

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90. What does broadband refer to?

Unfiltered

Other signals

Signals at all frequencies contribute to the measured value.

Vibration

Answer

Correct Answer: Signals at all frequencies contribute to the measured value.

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91. What does a bode plot display?

Magnitude of vibration at 1x the shaft speed and its amplitude relative to the shaft position

Phase of vibration at 1x the shaft speed and its frequency relative to the shaft position

Frequency of vibration at 1x the shaft speed and its amplitude relative to the shaft position

Magnitude of vibration at 1x the shaft speed and its phase relative to the shaft position

Answer

Correct Answer: Magnitude of vibration at 1x the shaft speed and its phase relative to the shaft position

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92. What is a bode plot?

A graph of position and speed plotted against time.

A graph of magnitude and phase plotted against time.

A graph of magnitude and phase plotted against speed.

A graph of acceleration and speed plotted against time.

Answer

Correct Answer: A graph of magnitude and phase plotted against speed.

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93. What is a baseline spectrum?

A vibration spectrum that is recorded when a machine is turned off.

A vibration spectrum that is recorded when a machine is in bad working condition.

A vibration spectrum that is recorded when a machine is turned on.

A vibration spectrum that is recorded when a machine is in good working condition.

Answer

Correct Answer: A vibration spectrum that is recorded when a machine is in good working condition.

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94. What is the term for the process of adjusting the distribution of mass in a rotating element to reduce vibratory forces generated by rotation?

Weighting

Spinning

Balancing

Off-balancing

Answer

Correct Answer: Balancing

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95. What is balancing?

The process of adjusting the distribution of mass in a rotating element to increase vibratory forces generated by rotation.

The process of adjusting the distribution of mass in a non-rotating element to increase vibratory forces generated by rotation.

The process of adjusting the distribution of mass in a non-rotating element to reduce vibratory forces generated by rotation.

The process of adjusting the distribution of mass in a rotating element to reduce vibratory forces generated by rotation.

Answer

Correct Answer: The process of adjusting the distribution of mass in a rotating element to reduce vibratory forces generated by rotation.

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96. What is the meaning of "Axial?"

A type of plane

Perpendicular to the longitudinal axis of a member

The force exerted by one object on another

The direction along the centerline of a shaft.

Answer

Correct Answer: The direction along the centerline of a shaft.

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97. What is the average value of a pure sine wave?

Two

One

Zero

Three

Answer

Correct Answer: Zero

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98. What does a power spectral density plot show?

The average power at each frequency

A spectral display of the power (voltage squared) at each frequency.

The power at each frequency over time

The power at each frequency over voltage

Answer

Correct Answer: A spectral display of the power (voltage squared) at each frequency.

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99. What does an anti-aliasing filter do?

It boosts frequencies higher than some fraction of the sample rate to maximize aliasing.

It does nothing to stop aliasing.

It stops frequencies higher than some fraction of the sample rate to minimize aliasing.

It randomly changes frequencies to create aliasing.

Answer

Correct Answer: It stops frequencies higher than some fraction of the sample rate to minimize aliasing.

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100. What is an anti-aliasing filter?

A low-pass filter designed to stop frequencies higher than some fraction of the sample rate to minimize aliasing.

Notch filter

A band-pass filter design

A high-pass filter design

Answer

Correct Answer: A low-pass filter designed to stop frequencies higher than some fraction of the sample rate to minimize aliasing.

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101. What does Amplitude refer to?

Time

Displacement, velocity, acceleration, voltage, current, force, or pressure.

Temperature

Mass

Answer

Correct Answer: Displacement, velocity, acceleration, voltage, current, force, or pressure.

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102. What is amplitude?

The magnitude of a quantity

The sum of a quantity and its zero value

The zero value of a quantity

The magnitude of a quantity's variation from its zero value

Answer

Correct Answer: The magnitude of a quantity's variation from its zero value

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103. What causes aliasing in a spectrum?

Not following the Nyquist theorem

Sampling data at too high a frequency

Sampling data at too low a sampling frequency

Using an analog input

Answer

Correct Answer: Sampling data at too low a sampling frequency

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104. What is aliasing?

A condition that causes low-frequency signals to appear in a spectrum at high frequencies.

A spectrum analysis problem that results from sampling data at too high a sampling frequency.

A spectrum analysis problem that results from sampling data at too low a sampling frequency.

The process of converting a signal from one form to another.

Answer

Correct Answer: A spectrum analysis problem that results from sampling data at too low a sampling frequency.

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105. What is accessibility?

Accessibility measures the related ease of access to various portions of an item for operation or maintenance.

The ability to walk and talk

The ability to read and write

The ability to see and hear

Answer

Correct Answer: Accessibility measures the related ease of access to various portions of an item for operation or maintenance.

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106. Accessibility is the related ease of what to various portions of an item?

Maintenance

Ease of access

Access

Operation

Answer

Correct Answer: Access

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107. What is accelerated stress testing?

A process on a sample of units to find hidden or latent failures after production.

A post-production process on a sample of units to precipitate hidden or latent failures.

A post-production process on a sample of units to find hidden or latent failures.

A process on a sample of units to find hidden or latent failures before production.

Answer

Correct Answer: A post-production process on a sample of units to precipitate hidden or latent failures.

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108. What is the main purpose of accelerated stress testing?

To precipitation hidden or latent failures.

To assess the quality of a product.

To find out the average lifespan of a product.

To prevent units from reaching the next level of assembly.

Answer

Correct Answer: To precipitation hidden or latent failures.

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109. Seismic sensors measure _____ vibration.

Relative

Absolute

Mixed

Vibrant

Answer

Correct Answer: Absolute

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110. What is absolute vibration?

Vibration of an object that is not periodic.

Vibration of an object relative to a fixed point in space.

Vibration of an object relative to another object.

Vibration of an object that is not fixed in space.

Answer

Correct Answer: Vibration of an object relative to a fixed point in space.

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111. What changes an analog signal into a digital signal?

A speakers

An amplifier

A voltage regulator

A digital converter

Answer

Correct Answer: A digital converter

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112. What is an analog signal?

A signal that remains constant in voltage or current

A signal that changes in voltage or current

A device that changes a digital signal into an analog signal

A digital signal

Answer

Correct Answer: A signal that changes in voltage or current

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113. What is the process of summing and dividing several like measurements to improve accuracy or lessen the effect of any asynchronous components called?

Addition

Division

Averaging

Multiplication

Answer

Correct Answer: Averaging

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114. What is the degree to which an item is in an operable and committable state at the start of a mission called?

Availability

Suitability

Mutability

Reliability

Answer

Correct Answer: Availability

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115. What does an angular rate sensor measure?

Rotational velocity (degrees or radians per second) around its sensitive axis.

Distance

Mass

Time

Answer

Correct Answer: Rotational velocity (degrees or radians per second) around its sensitive axis.

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116. What is the ambient environment?

The conditions that characterize the material

The material itself

The process of surrounding the material.

The conditions that characterize the air or other medium that surrounds the material.

Answer

Correct Answer: The conditions that characterize the air or other medium that surrounds the material.

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117. What is the purpose of an aggravated test?

To make the test item more stressed

To provide a margin of safety

To increase test time

To reduce test time or assure a margin of safety.

Answer

Correct Answer: To reduce test time or assure a margin of safety.

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118. What is an accelerometer?

A device that measures distance

A device that measures acceleration

A sensor, transducer, or pickup that converts acceleration into an electrical signal.

A device that measures speed

Answer

Correct Answer: A sensor, transducer, or pickup that converts acceleration into an electrical signal.

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119. What are the two common types of accelerometers?

Pneumatic and Hydraulic

Piezoresistive and Piezoelectric

Capacitive and Inductive

Thermocouple and RTD

Answer

Correct Answer: Piezoresistive and Piezoelectric

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120. What is the purpose of accelerated life testing?

To identify failure-prone, marginally strong elements by causing them to fail.

To test the product at levels much higher than those anticipated in the field.

To find the weakest point in the product.

To stress test the product.

Answer

Correct Answer: To identify failure-prone, marginally strong elements by causing them to fail.

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121. What is the meaning of traceable to NJST?

There is no such thing as NJST

NJST is an acronym for National Joseph Stalin tracing

A measure of the uncertainty of an instrument reading compared to that of a primary standard

The primary standard is located in NJST

Answer

Correct Answer: A measure of the uncertainty of an instrument reading compared to that of a primary standard

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122. What is the goal of equalization?

To amplify the sound

To make the sound clearer

To get rid of background noise

To compensate for the non-flat frequency response of human hearing

Answer

Correct Answer: To compensate for the non-flat frequency response of human hearing

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123. What is the axial position?

The change in a rotor's position or displacement along its axis and relative to a fixed point nearby.

The change in a rotor's position or displacement along its axis and relative to a moving point far away.

The change in a rotor's position or displacement along its axis and relative to a moving point nearby.

The change in a rotor's position or displacement along its axis and relative to a fixed point far away.

Answer

Correct Answer: The change in a rotor's position or displacement along its axis and relative to a fixed point nearby.

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124. What is another name for average responding?

Mode responding

Median responding

Geometric mean responding

Mean responding

Answer

Correct Answer: Mean responding

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125. What is the average responding proportional to?

The average of the absolute values of all input waveforms outside a specified frequency range

The average of the absolute values of all input waveforms

The average of the absolute values of all input waveforms within a specified frequency range

The average of all input waveforms

Answer

Correct Answer: The average of the absolute values of all input waveforms

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126. Auto-ranging is the capability of an instrument to switch ranges automatically. True or False?

True

False

Answer

Correct Answer: True

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127. What does auto-ranging refer to?

The capability of an instrument to switch ranges automatically.

The capability of an instrument to calibrate itself automatically.

The capability of an instrument to take readings in multiple units.

The use of multiple instruments to take readings simultaneously.

Answer

Correct Answer: The capability of an instrument to switch ranges automatically.

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128. What is the square root of the area under the ASD curve defined as?

The measure of acceleration power per Hz of analysis bandwidth

Power Spectral Density

The sum of the areas under the ASD curve

G RMS of acceleration

Answer

Correct Answer: G RMS of acceleration

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129. What does ASD stand for?

Amplitude Spectral Deviation

Acceleration Standard Deviation

Acceleration Square Deviation

Spectral Density

Answer

Correct Answer: Spectral Density

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130. What is the frequency in Hz of a 10 rad/s angular frequency?

80 Hz

16 Hz

160 Hz

8 Hz

Answer

Correct Answer: 160 Hz

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131. What is the torsional vibration frequency in radians per second?

Seconds

Frequency

Radian

Angular frequency

Answer

Correct Answer: Angular frequency

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132. Which of the following is NOT a desired machinery condition of alignment?

Parallel

Perpendicular

Least vibration

Colinear

Answer

Correct Answer: Least vibration

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133. What is the desired machinery condition when the axes of a machine's components are adjusted to be colinear, parallel or perpendicular?

Camber

Toe

Alignment

Scrub

Answer

Correct Answer: Alignment

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134. What is the relationship between accuracy and inaccuracy?

Accuracy is related to inaccuracy.

Accuracy is the same as inaccuracy.

Accuracy is the inverse of inaccuracy.

Accuracy is not related to inaccuracy.

Answer

Correct Answer: Accuracy is not related to inaccuracy.

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135. What is acceleration?

The rate of change of velocity with distance

The rate of change of time with space

The rate of change of velocity with time

The rate of change of distance with space

Answer

Correct Answer: The rate of change of velocity with time

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136. What is the rate of change of velocity with time called?

Time

Force

Velocity

Acceleration

Answer

Correct Answer: Acceleration

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137. How does an absorber work?

By amplifying vibration

By cancelling out vibration

By reflecting vibration

By converting vibration to heat

Answer

Correct Answer: By converting vibration to heat

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138. What is an absorber?

A device that produces heat

A device that produces light

A device capable of reducing or attenuating vibration

A device that amplifies sound

Answer

Correct Answer: A device capable of reducing or attenuating vibration

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139. What does the term "absolute" refer to in calibration?

A type of rock music

The furthest extent

A figure of speech

Calibration based on the primary standards of mass, length, and time

Answer

Correct Answer: Calibration based on the primary standards of mass, length, and time

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140. How do 6DOF machines produce vibration?

Repetitive shock

They use air-driven impact hammers to excite a vibrating plate or table

They use a vibrating plate or table to excite air-driven impact hammers

They use air-driven impact hammers to excite another 6DOF machine

Answer

Correct Answer: They use air-driven impact hammers to excite a vibrating plate or table

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Acoustical Engineering MCQs | Topic-wise

MCQ on Acoustic modelling software	MCQ on Acoustical Modeling
MCQ on Acoustical and Audio Measurements	MCQ on Acoustics Design Practicum
MCQ on Architectural Acoustics	MCQ on Audio Visual System Design
MCQ on Basic Acoustical Engineering	MCQ on Basic Audiology
MCQ on Ear Anatomy	MCQ on Electroacoustics
MCQ on Environmental Acoustics	MCQ on Measurement of Noise
MCQ on Microphones	MCQ on Musical Acoustics
MCQ on Noise & Vibration Control	MCQ on Noise Control
MCQ on Psychoacoustics	MCQ on Sound Insulation
General Acoustical Engineering MCQs