Mechanical Vibrations Mid - I, September - 2014

1.The time taken, by a vibrating body to complete one cycle, is known as
  • period
  • frequency
  • resonance
  • damping
Answer: A
2.Resonance is a phenomenon in which the frequency of the external exciting force
  • is half the natural frequency of the system
  • is double the natural frequency of the system
  • coincides with the natural frequency of the system
  • none of the above
Answer: C
3.If the particles of a body vibrate parallel to the axis of the body, then the body is said to have
  • transverse vibration
  • longitudinal vibration
  • torsional vibration
  • none of the above
Answer: B
4.If the particles of a body vibrates along a circular arc, whose centre lies on the axis of the shaft, Then the body is said to have
  • transverse vibration
  • longitudinal vibration
  • torsional vibration
  • none of the above
Answer: C
5.The natural frequency of the free longitudinal vibrations is the
  • same as the natural period of vibrations
  • reciprocal of the natural period of vibrations
  • twice the natural period of vibrations
  • none of the above
Answer: B
6.The natural frequency of a system is a function of
  • stiffness of the system
  • mass of the system
  • amplitude of oscillation
  • both(A)&(B).
Answer: D
7.At certain speed, the rotating shaft ends to vibrate violently in transverse direction. Then speed is called
  • whirling speed
  • critical speed
  • whipping speed
  • all of the above
Answer: D
8.The amount of damping, necessary for a system to be critically damped, is known as
  • damping factor
  • magnification factor
  • critical damping co-efficient
  • none of the above
Answer: C
9.In a light or under damped vibrating system, the natural logarithm of the ratio of any two Successive amplitudes is known as
  • damping factor
  • magnification factor
  • critical damping co-efficient
  • logarithmic decrement
Answer: D
10.An over damped system is distributed from equilibrium position with some initial velocity. the System will
  • not cross the equilibrium position
  • vibrate about equilibrium position
  • immediately return to the equilibrium position
  • none of the above
Answer: A
11.The periodic time and frequency of a body will be same if it is suspended at the________________
Answer: Point of suspension or at the point of percussion
12.If the length of the string of a simple pendulum is made four times the original length ,the time period will be ____________________
Answer: Doubled
13.At mean position, the velocity of a body moving with simple harmonic motion is _______________
Answer: Minimum
14.The number of cycles per second is known as _________________________
Answer: Frequency
15.Periodic time is the time taken by a particle for one complete ____________________
Answer: Oscillation
16.The product of frequency and time period of a body moving with simple harmonic motion is equal To ______________________________
Answer: One
17.Accelero meter is used to measure ___________________________
Answer: High amplitudes
18.In laplace transforms step function are used to _____________________
Answer: Derive governing equations
19.Free vibrations take place when an elastic system not acted upon by any steady _________________
Answer: Exciting forces
20.A vibrating system may encounter damping forces of different types like_____________________
Answer: Inter molecular friction, sliding friction