Mechanical Vibration MCQ

71. Which one of the following relations with usual notations will hold good in a dynamic vibration absorber system under tuned conditions?

  1. k1k2 = m1m2
  2. k1m2 = m1k2
  3. k1m1 = k2m2
  4. k1+ k2 = m1 + m2
Answer
Answer. b

72. The damping force is constant in magnitude but oppo0site in direction to that of motion of vibrating bodies in case of

  1. Viscous damping
  2. Columb damping
  3. Slip damping
  4. Structural damping
Answer
Answer. b

73. At resonance, the amplitude of vibration is

  1. very large
  2. small
  3. zero
  4. depend on frequency
Answer
Answer. a

74. In case of critical damping the damping factor ratio is

  1. equal to one
  2. equal to zero
  3. less than one
  4. greater than one
Answer
Answer. a

75. A system has viscous damped output. There is no steady-state lag if input is

  1. Unit step displacement
  2. Step velocity
  3. Harmonic
  4. Step velocity with error-rate damping
Answer
Answer. d

76. The maximum displacement from the mean position of a vibrating body is called

  1. Frequency
  2. Phase
  3. Amplitude
  4. Resonance
Answer
Answer. c

77. What is the number of nodes in a shaft carrying three rotors?

  1. 2
  2. zero
  3. 4
  4. 3
Answer
Answer. a

78. A vibrating system is said to be critically damped when the damping factor is

  1. unity
  2. zero
  3. 1/2
  4. infinity
Answer
Answer. a

79. When a system is subjected to force vibrations, then under steady-state conditions

  1. it vibrates at its natural frequency
  2. it vibrates at the imposed frequency
  3. it vibrates at the mean of natural and imposed frequencies
  4. none of the above
Answer
Answer. b

80. Critical or whirling speed is the speed at which the shaft tends to vibrate violently in

  1. Transverse direction
  2. Longitudinal direction
  3. Linear direction
  4. None of these
Answer
Answer. a
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