Which of the following statements is/are false for pneumatic isolators ? 1. Pneumatic isolators are used when driving frequencies below 10 Hz are present 2. Nausea is caused due to noise at low frequencies 3. At high natural frequencies, isolators can obtain efficiency of 90% 4. Pneumatic isolators have limited load carrying capacity

All the above statements are false

Which of the following statements is/are true? 1. Magnification factor is minimum at resonance 2. The maximum value of amplification factor increases as damping factor decreases 3. The maximum value of amplification factor increases as damping factor increases 4. Magnification factor is maximum at resonance

All the above statements are true

Which of the following statements is/are true for elastomers?

Elastomers can be used for static deflections up to 12 mm

Elastomers can provide natural frequencies below 5 Hz

Elastomers have good performance at high frequencies

All the above statements are true

Which of the following statements is/are true for coulomb damping? 1. Coulomb damping occurs due to friction between two lubricated surfaces 2. Damping force is opposite to the direction of motion of vibrating body 3. For smooth surfaces, coefficient of friction depends upon velocity 4. Damping force depends upon the rubbing velocity between two rubbing surfaces

All the above statements are true

Which of the following conditions should be satisfied for complete balancing of multi-cylinder inline engines?

Primary couples should be balanced

Secondary couples should be balanced

Which of the following conditions is/are to be satisfied by the seismometer for it to be used as velometer?

It's output signal should be proportional to relative acceleration of the vibrating body

It's natural frequency should be large

It's natural frequency should be small

It's output signal should be proportional to relative acceleration of the vibrating body

When a person enters a far field from a near field, the sound pressure level drops off at the rate of _______

2 dB per 1/4th distance from point source

2 dB per doubling the distance from point source

4 dB per half distance from point source

6 dB per doubling the distance from point source

What is the effect of damping on phase angle at resonance frequency?

Phase angle increases as damping decreases

Phase angle increases as damping increases

Damping has no effect on phase angle

Phase angle increases as damping decreases

What is meant by Reverberant chamber?

Chambers having walls, ceiling and flooring covered by sound absorbing materials

Chambers having walls, ceiling and flooring acoustically reflected

Chambers having walls, ceiling and flooring covered by sound absorbing materials

Chambers having walls and ceiling made of different absorbing material

What is meant by geometric modeling?

Representation of an object with graphical information

Representation of an object with non-graphical information

What is meant by coupled differential equation?

The differential equation in which only rectilinear motions exit

The differential equation in which only angular motions exit

The differential equation in which both rectilinear and angular motions exit

What happens when sound waves impinge on fiber boards?

Sound energy is converted into mechanical energy

Sound energy is converted into vibrational energy

Sound energy is converted into heat energy

Sound energy is converted into mechanical energy

What are discrete parameter systems?

Systems which have no degree of freedom

Systems which have infinite number of degree of freedom

Systems which have finite number of degree of freedom

Systems which have no degree of freedom

Transmissibility is the ratio of ______

force transmitted to the supporting structure and force impressed upon the system

displacement amplitude of mass and displacement amplitude of supporting structure

Secondary force in reciprocating engine mechanism is caused due to _______

oscillation of reciprocating parts

obliquity of arrangement of reciprocating parts

Magnification factor is the ratio of ______

amplitude of unsteady state vibrations and zero frequency distribution

zero frequency deflection and amplitude of steady state vibrations

amplitude of steady state vibrations and zero frequency deflection

amplitude of unsteady state vibrations and zero frequency distribution

At which frequency ratio, phase angle increases as damping factor increases?

When frequency ratio is more than unity

When frequency ratio is less than unity

When frequency ratio is more than unity

51 + Mcqs in Dynamics of Machinery Questions in Mechanical Engineering Questions Page 1 McqOptions

1.	Which of the following statements is/are false for pneumatic isolators ? 1. Pneumatic isolators are used when driving frequencies below 10 Hz are present 2. Nausea is caused due to noise at low frequencies 3. At high natural frequencies, isolators can obtain efficiency of 90% 4. Pneumatic isolators have limited load carrying capacity
A.	Only statement 1
B.	Only statement 3
C.	Only statement 2, 4
D.	All the above statements are false
Answer» C. Only statement 2, 4

Discussion

2.	Which of the following statements is/are true? 1. Magnification factor is minimum at resonance 2. The maximum value of amplification factor increases as damping factor decreases 3. The maximum value of amplification factor increases as damping factor increases 4. Magnification factor is maximum at resonance
A.	Statement 1 and statement 2
B.	Statements 1,2 and 3
C.	Statement 2 and statement 4
D.	All the above statements are true
Answer» D. All the above statements are true

Discussion

3.	Which of the following statements is/are true for elastomers?
A.	Elastomers can be used for static deflections up to 12 mm
B.	Elastomers can provide natural frequencies below 5 Hz
C.	Elastomers have good performance at high frequencies
D.	All the above statements are true
Answer» E.

Discussion

4.	Which of the following statements is/are true for coulomb damping? 1. Coulomb damping occurs due to friction between two lubricated surfaces 2. Damping force is opposite to the direction of motion of vibrating body 3. For smooth surfaces, coefficient of friction depends upon velocity 4. Damping force depends upon the rubbing velocity between two rubbing surfaces
A.	Only statement 1
B.	Statement 2, 3 and statement 4
C.	Only statement 2
D.	All the above statements are true
Answer» D. All the above statements are true

Discussion

5.	Which of the following statements is/are true primary/secondary couple? 1. Secondary couple does not act on V engine 2. Primary couple acts on V engine 3. Secondary couple acts on reciprocating masses of multi-cylinder inline engines 4. Primary couple acts on reciprocating masses of multi-cylinder inline engines
A.	1 and 2
B.	2, 3 and 4
C.	1, 3 and 4
D.	All of the above
Answer» D. All of the above

Discussion

6.	Which of the following vibrations are classified according to magnitude of actuating force?
A.	Torsional vibrations
B.	Deterministic vibrations
C.	Transverse vibrations
D.	All of the above
Answer» C. Transverse vibrations

Discussion

7.	Which part of the human ear is divided by the basilar membrane?
A.	Ear drum
B.	Helicontrema
C.	Cochlea
D.	Eustachian tube
Answer» D. Eustachian tube

Discussion

8.	Which type of earplugs contain silicon rubber and a fixing agent?
A.	Semi insert protectors
B.	Custom moulded earplugs
C.	Pre-fabricated earplugs
D.	Canal caps
Answer» C. Pre-fabricated earplugs

Discussion

9.	Which type of frequency measuring instrument has multiple reeds of different natural frequency to measure vibrations?
A.	Fullarton tachometer
B.	Frahm Tachometer
C.	Both a. and b.
D.	None of the above
Answer» C. Both a. and b.

Discussion

10.	Which type of instruments do not require separate power source for measuring vibratory response of a vibratory system?
A.	Active instruments
B.	Passive instruments
C.	Both a. and b.
D.	None of the above
Answer» C. Both a. and b.

Discussion

11.	Which of the following methods can be used to reduce excitation level at the source?
A.	Lubrication of joints
B.	Balancing inertia forces
C.	Both a. and b.
D.	None of the above
Answer» D. None of the above

Discussion

12.	Which of the following methods can be used to control the noise level at source?
A.	Changing design process
B.	Using sound enclosures
C.	Controlling vibration
D.	All of the above
Answer» E.

Discussion

13.	Which of the following is a type of untuned vibration absorber?
A.	Houdaille damper
B.	Torsional vibration absorber
C.	Centrifugal pendulum absorber
D.	All of the above
Answer» B. Torsional vibration absorber

Discussion

14.	Which of the following factors are not responsible for unbalancing in rotating systems?
A.	Errors
B.	Tolerances
C.	Shape of the rotor
D.	None of the above
Answer» E.

Discussion

15.	Which of the following construction equipments have highest noise level?
A.	Compressors
B.	Generators
C.	Pneumatic wrenches
D.	Pumps
Answer» D. Pumps

Discussion

16.	Which of the following conditions should be satisfied for static balancing? 1. Dynamic forces acting on the system should be zero 2. Couple acting on the system due to dynamic force should be zero 3. Centrifugal forces acting on the system should be zero 4. Couple acting on the system due to centrifugal forces should be zero
A.	Condition 1 and condition 2
B.	Condition 1 and condition 3
C.	Condition 3 and condition 4
D.	All of the above
Answer» C. Condition 3 and condition 4

Discussion

17.	Which of the following conditions should be satisfied for complete balancing of multi-cylinder inline engines?
A.	Primary couples should be balanced
B.	Secondary couples should be balanced
C.	Both a. and b.
D.	None of the above
Answer» D. None of the above

Discussion

18.	Which of the following conditions is/are to be satisfied by the seismometer for it to be used as velometer?
A.	It's natural frequency should be large
B.	It's natural frequency should be small
C.	It's output signal should be proportional to relative acceleration of the vibrating body
D.	None of the above
Answer» C. It's output signal should be proportional to relative acceleration of the vibrating body

Discussion

19.	Which of the following absorptive treatment can be used to cover the interior of a box to prevent the reverberant sound?
A.	Open cell foam
B.	Glass fiber mat
C.	Both a. and b.
D.	None of the above
Answer» D. None of the above

Discussion

20.	Which instrument integrates sound pressure as a function of time over a period of time?
A.	Noise dosimeter
B.	FFT analyzer
C.	Both a. and b.
D.	None of the above
Answer» B. FFT analyzer

Discussion

21.	Which basic document describes general requirements for measurement and evaluation of machine vibrations using shaft measurements?
A.	ISO – 10816-1
B.	ISO – 7919-1
C.	Both a. and b.
D.	None of the above
Answer» C. Both a. and b.

Discussion

22.	Which among the following is not considered when reference standards are used in the field of mechanical vibration and shock, monitoring and analysis of machines?
A.	Terminology
B.	Methods of testing
C.	Methods of measurement
D.	None of the above
Answer» E.

Discussion

23.	When a person enters a far field from a near field, the sound pressure level drops off at the rate of _______
A.	2 dB per 1/4th distance from point source
B.	2 dB per doubling the distance from point source
C.	4 dB per half distance from point source
D.	6 dB per doubling the distance from point source
Answer» E.

Discussion

24.	What will be the sound power level, if a machine generates 20 W power?
A.	124 dB
B.	133 dB
C.	150 dB
D.	200 dB
Answer» C. 150 dB

Discussion

25.	What is the effect of damping on phase angle at resonance frequency?
A.	Phase angle increases as damping increases
B.	Damping has no effect on phase angle
C.	Phase angle increases as damping decreases
D.	None of the above
Answer» C. Phase angle increases as damping decreases

Discussion

26.	What is meant by Reverberant chamber?
A.	Chambers having walls, ceiling and flooring acoustically reflected
B.	Chambers having walls, ceiling and flooring covered by sound absorbing materials
C.	Chambers having walls and ceiling made of different absorbing material
D.	None of the above
Answer» B. Chambers having walls, ceiling and flooring covered by sound absorbing materials

Discussion

27.	What is meant by geometric modeling?
A.	Representation of an object with graphical information
B.	Representation of an object with non-graphical information
C.	Both a. and b.
D.	None of the above
Answer» D. None of the above

Discussion

28.	What is meant by coupled differential equation?
A.	The differential equation in which only rectilinear motions exit
B.	The differential equation in which only angular motions exit
C.	The differential equation in which both rectilinear and angular motions exit
D.	None of the above
Answer» D. None of the above

Discussion

29.	What happens when sound waves impinge on fiber boards?
A.	Sound energy is converted into vibrational energy
B.	Sound energy is converted into heat energy
C.	Sound energy is converted into mechanical energy
D.	All of the above
Answer» C. Sound energy is converted into mechanical energy

Discussion

30.	What are the adverse effects of noise on the organizations?
A.	Compensation claims
B.	Productivity
C.	Both a. and b.
D.	None of the above
Answer» D. None of the above

Discussion

31.	What are discrete parameter systems?
A.	Systems which have infinite number of degree of freedom
B.	Systems which have finite number of degree of freedom
C.	Systems which have no degree of freedom
D.	None of the above
Answer» C. Systems which have no degree of freedom

Discussion

32.	Two springs have spring stiffness of 1500 N/m and 2000 N/m respectively. If they are connected in series, what is the spring stiffness if they are replaced by an equivalent system.3500 N/m
A.	3500 N/m
B.	1166 N/m
C.	857.63 N/m
D.	None of the above
Answer» D. None of the above

Discussion

33.	Transmissibility is the ratio of ______
A.	force transmitted to the supporting structure and force impressed upon the system
B.	displacement amplitude of mass and displacement amplitude of supporting structure
C.	both a. and b.
D.	none of the above
Answer» D. none of the above

Discussion

34.	The process of maintaining appropriate noise level without considering economic factors is called as _____
A.	noise control
B.	noise reduction
C.	both a. and b.
D.	none of the above
Answer» C. both a. and b.

Discussion

35.	The noise level generated by domestic air conditioner ranges between _________
A.	38 dB to 70 dB
B.	35 dB to 52 dB
C.	62 dB to 88 dB
D.	50 dB to 60 dB
Answer» E.

Discussion

36.	The motion of a system executing harmonic motion with one natural frequency is known as _______
A.	principal mode of vibration
B.	natural mode of vibration
C.	both a. and b.
D.	none of the above
Answer» D. none of the above

Discussion

37.	Secondary force in reciprocating engine mechanism is caused due to _______
A.	S.H.M. of reciprocating parts
B.	oscillation of reciprocating parts
C.	obliquity of arrangement of reciprocating parts
D.	all of the above
Answer» D. all of the above

Discussion

38.	Magnification factor is the ratio of ______
A.	zero frequency deflection and amplitude of steady state vibrations
B.	amplitude of steady state vibrations and zero frequency deflection
C.	amplitude of unsteady state vibrations and zero frequency distribution
D.	none of the above
Answer» C. amplitude of unsteady state vibrations and zero frequency distribution

Discussion

39.	In which type of vibrations, amplitude of vibration goes on decreasing every cycle?
A.	Damped vibrations
B.	Undamped vibrations
C.	Both a. and b.
D.	None of the above
Answer» B. Undamped vibrations

Discussion

40.	Elastomeric foam used as a sound absorber is made of ___________
A.	Non-porous material
B.	Porous material
C.	Perforated material
D.	Resonator
Answer» C. Perforated material

Discussion

41.	Eddy current damping is an example of _____
A.	Coulomb damping
B.	Hysteresis damping
C.	Viscous damping
D.	Dry friction damping
Answer» D. Dry friction damping

Discussion

42.	Determine velocity of sound in air at 50o. (For air, γ = 1.4)
A.	1002.5 m/s
B.	360.45 m/s
C.	350 m/s
D.	None of the above
Answer» C. 350 m/s

Discussion

43.	Determine magnitude of balancing mass required if 250 mm is the radius of rotation. Masses of A, B and C are 300 kg, 250 kg and 100 kg which have radii of rotation as 50 mm, 80 mm and 100 mm respectively . The angles between the consecutive masses are 110° and 270° respectively.
A.	45.36 kg
B.	47.98 kg
C.	40.50 kg
D.	None of the above
Answer» C. 40.50 kg

Discussion

44.	Determine natural frequency of a system, which has equivalent spring stiffness of 30000 N/m and mass of 20 kg?
A.	12.32 Hz
B.	4.10 Hz
C.	6.16 Hz
D.	None of the above
Answer» D. None of the above

Discussion

45.	Determine logarithmic decrement, if the amplitude of a vibrating body reduces to 1/6th in two cycles.
A.	0.223
B.	0.8958
C.	0.3890
D.	None of the above
Answer» C. 0.3890

Discussion

46.	Calculate natural frequency of damped vibration, if damping factor is 0.52 and natural frequency of the system is 30 rad/sec which consists of machine supported on springs and dashpots.
A.	25.62 rad/sec
B.	20.78 rad/sec
C.	14.4 rad/sec
D.	15.33 rad/sec
Answer» B. 20.78 rad/sec

Discussion

47.	Calculate damped natural frequency, if a spring mass damper system is subjected to periodic disturbing force of 30 N. Damping coefficient is equal to 0.76 times of critical damping coefficient and undamped natural frequency is 5 rad/sec
A.	3.99 rad/sec
B.	2.13 rad/sec
C.	4.12 rad/sec
D.	3.24 rad/sec
Answer» E.

Discussion

48.	Calculate critical speed of a vehicle which moves on a road having sinusoidal profile of wavelength 2.5 m. The mass of the vehicle is 300 kg and natural frequency of its spring suspension system is 8 rad/sec
A.	4.15 m/sec
B.	3.18 m/sec
C.	2.36 m/sec
D.	None of the above
Answer» C. 2.36 m/sec

Discussion

49.	At which frequency ratio, phase angle increases as damping factor increases?
A.	When frequency ratio is less than unity
B.	When frequency ratio is more than unity
C.	When frequency ratio is zero
D.	All of the above
Answer» B. When frequency ratio is more than unity

Discussion

50.	At which angle primary unbalanced force in reciprocating engine mechanism is maximum?
A.	0°
B.	90°
C.	360°
D.	All of the above
Answer» B. 90°

Discussion

Explore topic-wise MCQs in Mechanical Engineering Questions.

Which of the following statements is/are true for elastomers?

Which of the following vibrations are classified according to magnitude of actuating force?

Which part of the human ear is divided by the basilar membrane?

Which type of earplugs contain silicon rubber and a fixing agent?

Which type of frequency measuring instrument has multiple reeds of different natural frequency to measure vibrations?

Which type of instruments do not require separate power source for measuring vibratory response of a vibratory system?

Which of the following methods can be used to reduce excitation level at the source?

Which of the following methods can be used to control the noise level at source?

Which of the following is a type of untuned vibration absorber?

Which of the following factors are not responsible for unbalancing in rotating systems?

Which of the following construction equipments have highest noise level?

Which of the following conditions should be satisfied for complete balancing of multi-cylinder inline engines?

Which of the following conditions is/are to be satisfied by the seismometer for it to be used as velometer?

Which of the following absorptive treatment can be used to cover the interior of a box to prevent the reverberant sound?

Which instrument integrates sound pressure as a function of time over a period of time?

Which basic document describes general requirements for measurement and evaluation of machine vibrations using shaft measurements?

Which among the following is not considered when reference standards are used in the field of mechanical vibration and shock, monitoring and analysis of machines?

When a person enters a far field from a near field, the sound pressure level drops off at the rate of _______

What will be the sound power level, if a machine generates 20 W power?

What is the effect of damping on phase angle at resonance frequency?

What is meant by Reverberant chamber?

What is meant by geometric modeling?

What is meant by coupled differential equation?

What happens when sound waves impinge on fiber boards?

What are the adverse effects of noise on the organizations?

What are discrete parameter systems?

Two springs have spring stiffness of 1500 N/m and 2000 N/m respectively. If they are connected in series, what is the spring stiffness if they are replaced by an equivalent system.3500 N/m

Transmissibility is the ratio of ______

The process of maintaining appropriate noise level without considering economic factors is called as _____

The noise level generated by domestic air conditioner ranges between _________

The motion of a system executing harmonic motion with one natural frequency is known as _______

Secondary force in reciprocating engine mechanism is caused due to _______

Magnification factor is the ratio of ______

In which type of vibrations, amplitude of vibration goes on decreasing every cycle?

Elastomeric foam used as a sound absorber is made of ___________

Eddy current damping is an example of _____

Determine velocity of sound in air at 50o. (For air, γ = 1.4)

Determine magnitude of balancing mass required if 250 mm is the radius of rotation. Masses of A, B and C are 300 kg, 250 kg and 100 kg which have radii of rotation as 50 mm, 80 mm and 100 mm respectively . The angles between the consecutive masses are 110° and 270° respectively.

Determine natural frequency of a system, which has equivalent spring stiffness of 30000 N/m and mass of 20 kg?

Determine logarithmic decrement, if the amplitude of a vibrating body reduces to 1/6th in two cycles.

Calculate natural frequency of damped vibration, if damping factor is 0.52 and natural frequency of the system is 30 rad/sec which consists of machine supported on springs and dashpots.

Calculate damped natural frequency, if a spring mass damper system is subjected to periodic disturbing force of 30 N. Damping coefficient is equal to 0.76 times of critical damping coefficient and undamped natural frequency is 5 rad/sec

Calculate critical speed of a vehicle which moves on a road having sinusoidal profile of wavelength 2.5 m. The mass of the vehicle is 300 kg and natural frequency of its spring suspension system is 8 rad/sec

At which frequency ratio, phase angle increases as damping factor increases?

At which angle primary unbalanced force in reciprocating engine mechanism is maximum?