Mechanical Vibration MCQ

21. According to law of transmissibility of forces, effect of force acting on the body is

  1. different at different points of the body
  2. minimum when it acts at centre of gravity of the body
  3. maximum when it acts at centre of gravity of the body
  4. same at every point in its line of action
Answer. d

22. In viscous damping, the damping force is _________ velocity of vibrating body.

  1. proportional to
  2. inversely proportional to
  3. square of
  4. cube of
Answer. a

23. When will the resonance occur for an underdamped harmonic oscillator?

  1. When excitation frequency is greater than the undamped natural frequency
  2. When excitation frequency is less than undamped natural frequency
  3. When excitation frequency is equal to undamped natural frequency
  4. Never occurs
Answer. c

24. Though vibration cannot be eliminated completely, it can be suppressed to a greater extent using

  1. Damper
  2. Accumulator
  3. Receiver
  4. Reducer
Answer. a

25. If there is a gradual reduction in amplitude of vibration with time, the body is said to be in

  1. Free vibration
  2. Forced vibration
  3. Damped vibration
  4. Undamped vibration
Answer. c

26. Natural frequency of a system is due to

  1. free vibration
  2. forced vibrations
  3. resonance
  4. damping
Answer. a

27. Which of the following purposes is served by critical damping?

  1. It provides basis of determining critical damping
  2. It predicts nature of vibration
  3. It provides a measure of the relative amount of damping in a system.
  4. It enables measurement of damping.
Answer. b

28. The system in which the amplitude of vibration decreases with time and ratio of amplitude of successive oscillate being constant is known as

  1. Critically damped system
  2. Underdamped system
  3. Undamped system
  4. Overdamped system
Answer. b

29. Whirling speed of a shaft coincides with the natural frequency of its

  1. Longitudinal vibration
  2. Transverse vibration
  3. Torsional vibration
  4. Coupled bending torsional vibration
Answer. b

30. Damping force per unit velocity is known as

  1. Damping factor
  2. Damping coefficient
  3. Logarithmic decrement
  4. Stiffness of the spring
Answer. b