Dynamics of Machinery Test - Set - 3

1)   Which of the following instruments measure amplitude of a vibrating body?

a. Vibrometers
b. Seismometer
c. Both a. and b.
d. None of the above
Answer  Explanation  Related Ques

ANSWER: Both a. and b.

Explanation:
No explanation is available for this question!


2)   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  Explanation  Related Ques

ANSWER: Passive instruments

Explanation:
No explanation is available for this question!


3)   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  Explanation  Related Ques

ANSWER: Frahm Tachometer

Explanation:
No explanation is available for this question!


4)   Which of the following statements is true about stroboscope?

a. Stroboscope is non-contact type frequency instrument
b. Stroboscope can measure frequency upto 5 Hz
c. Stroboscope uses electromagnetic radiations to measure frequency
d. All of the above
Answer  Explanation  Related Ques

ANSWER: Stroboscope is non-contact type frequency instrument

Explanation:
No explanation is available for this question!


5)   Temperature monitoring technique uses which of the following devices to measure temperature of the machining surfaces?

a. Pyrometers
b. Thermocouples
c. Thermometers
d. All of the above
Answer  Explanation  Related Ques

ANSWER: All of the above

Explanation:
No explanation is available for this question!


6)   What is the function of the controller in active vibration isolation systems?

a. Detect vibrations to be controlled
b. Reposition the masses
c. Interpret detected vibrations and execute commands
d. All of the above
Answer  Explanation  Related Ques

ANSWER: Interpret detected vibrations and execute commands

Explanation:
No explanation is available for this question!


7)   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  Explanation  Related Ques

ANSWER: both a. and b.

Explanation:
No explanation is available for this question!


8)   A vibrating machine of 100 kg is mounted on a rubber pad which has stiffness of 500 N/m. Determine force transmitted to the foundation if the unbalanced force 500 N acts on it. The frequency ratio (ω/ωn) is 1.5 and ξ = 0.5

a. 461.62 N
b. 400.23 N
c. 450 N
d. Insufficient data
Answer  Explanation  Related Ques

ANSWER: 461.62 N

Explanation:
No explanation is available for this question!


9)   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  Explanation  Related Ques

ANSWER: Only statement 3

Explanation:
No explanation is available for this question!


10)   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  Explanation  Related Ques

ANSWER: All the above statements are true

Explanation:
No explanation is available for this question!


11)   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  Explanation  Related Ques

ANSWER: All of the above

Explanation:
No explanation is available for this question!


12)   What is the function of frequency analyzer?

a. It analysis noise signal in frequency domain into various frequency bands by magnetically separating the signal
b. It analysis noise signal in frequency domain into various frequency bands by electronically separating the signal
c. It analysis noise signal in frequency domain into various frequency bands by electromagnetically separating the signal
d. None of the above
Answer  Explanation  Related Ques

ANSWER: It analysis noise signal in frequency domain into various frequency bands by electronically separating the signal

Explanation:
No explanation is available for this question!


13)   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  Explanation  Related Ques

ANSWER: Noise dosimeter

Explanation:
No explanation is available for this question!


14)   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  Explanation  Related Ques

ANSWER: Both a. and b.

Explanation:
No explanation is available for this question!


15)   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  Explanation  Related Ques

ANSWER: noise reduction

Explanation:
No explanation is available for this question!


16)   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  Explanation  Related Ques

ANSWER: 6 dB per doubling the distance from point source

Explanation:
No explanation is available for this question!


17)   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  Explanation  Related Ques

ANSWER: Sound energy is converted into heat energy

Explanation:
No explanation is available for this question!


18)   The resonant frequency of a mass-spring system depends upon ________

a. stiffness
b. surface density
c. depth of air space
d. all of the above
Answer  Explanation  Related Ques

ANSWER: all of the above

Explanation:
No explanation is available for this question!


19)   Elastomeric foam used as a sound absorber is made of ___________

a. Non-porous material
b. Porous material
c. Perforated material
d. Resonator
Answer  Explanation  Related Ques

ANSWER: Porous material

Explanation:
No explanation is available for this question!


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

a. Ear drum
b. Helicontrema
c. Cochlea
d. Eustachian tube
Answer  Explanation  Related Ques

ANSWER: Cochlea

Explanation:
No explanation is available for this question!


21)   Calculate logarithmic decrement if damping factor is 0.33.

a. 1.36
b. 3.23
c. 5.16
d. 2.19
Answer  Explanation  Related Ques

ANSWER: 2.19

Explanation:
No explanation is available for this question!


22)   Calculate coefficient of viscous damper, if the system is critically damped.
Consider the following data:

1. Mass of spring mass damper system = 350 kg
2. Static deflection = 2 x 10–3 m
3. Natural frequency of the system = 60 rad/sec


a. 100.5 x 103 N-s/m
b. 80 x 103 N-s/m
c. 42 x 103 N-s/m
d. None of the above
Answer  Explanation  Related Ques

ANSWER: 42 x 103 N-s/m

Explanation:
No explanation is available for this question!


23)   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  Explanation  Related Ques

ANSWER: 0.8958

Explanation:
No explanation is available for this question!