# Dynamics of Machinery 1

Mechanical Engineering MCQ Question Papers: DRDO, ISRO, Interview

Subject: Dynamics of Machinery 1

Part 1: List for questions and answers of Dynamics of Machinery

Q1. 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

Q2. Calculate logarithmic decrement if damping factor is 0.33.
a) 1.36
b) 3.23
c) 5.16
d) 2.19

Q3. Which part of the human ear is divided by the basilar membrane?
a) Ear drum
b) Helicontrema
c) Cochlea
d) Eustachian tube

Q4. Elastomeric foam used as a sound absorber is made of ___________
a) Non-porous material
b) Porous material
c) Perforated material
d) Resonator

Q5. 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

Q6. What happens when sound waves impinge on fiber boards?
a) Sound energy is converted into vibration energy
b) Sound energy is converted into heat energy
c) Sound energy is converted into mechanical energy
d) All of the above

Q7. 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

Q8. The process of maintaining appropriate noise level without considering economic factors is called as _____
a) Noise control
b) Noise reduction
c) Both a. & b
d) None of the above

Q9. What are the adverse effects of noise on the organizations?
a) Compensation claims
b) Productivity
c) Both a. & b
d) None of the above

Q10. Which instrument integrates sound pressure as a function of time over a period of time?
a) Noise dosimeter
b) Fat analyzer
c) Both a. & b
d) None of the above

Q11. 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

Q12. 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

Q13. 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. & b
d) None of the above

Q14. 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

Q15. 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

Q16. Which of the following statements is true about stroboscope?
a) Stroboscope is non-contact type frequency instrument
b) Stroboscope can measure frequency up to 5 Hz
c) Stroboscope uses electromagnetic radiations to measure frequency
d) All of the above

Q17. Which type of frequency measuring instrument has multiple reeds of different natural frequency to measure vibrations?
a) Fullerton tachometer
b) Frahm tachometer
c) Both a. & b
d) None of the above

Q18. 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

Q19. 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

Q20. Which part of the human ear is divided by the basilar membrane?
a) Ear drum
b) Helicontrema
c) Cochlea
d) Eustachian tube

Part 1: List for questions and answers of Dynamics of Machinery