Mechanical Gate Subject

Vibrations Mechanical previous year questions with answer


Ques 21 GATE 2014 SET-3

The damping ratio of a single degree of freedom spring-mass-damper system with mass of 1 kg, stiffness 100 N/m and viscous damping coefficient of 25 N·s/m is _______


1.25 is the correct answer.


Ques 22 GATE 2014 SET-2

In vibration isolation, which one of the following statements is NOT correct regarding Transmissibility (T)?

A

T is nearly unity at small excitation frequencies

B

T can be always reduced by using higher damping at any excitation frequency

C

T is unity at the frequency ratio of 2

D

T is infinity at resonance for undamped systems



Ques 23 GATE 2014 SET-2

What is the natural frequency of the spring mass system shown below? The contact between the block and the inclined plane is frictionless. The mass of the block is denoted by m and the spring constants are denoted by k1 and k2.

A

√(k1 + k2)/2m

B

√(k1 + k2)/4m

C

√k1 − k2/m

D

√(k1 + k2)/m



Ques 24 GATE 2014 Set-1

Critical damping is the

A

largest amount of damping for which no oscillation occurs in free vibration

B

smallest amount of damping for which no oscillation occurs in free vibration

C

largest amount of damping for which the motion is simple harmonic in free vibration

D

smallest amount of damping for which the motion is simple harmonic in free vibration



Ques 25 GATE 2014 Set-1

Consider a cantilever beam, having negligible mass and uniform flexural rigidity, with length 0.01 m. The frequency of vibration of the beam, with a 0.5 kg mass attached at the free tip, is 100 Hz. The flexural rigidity (in N.m2) of the beam is _______


0.064 to 0.067 is the correct answer.


Ques 26 GATE 2014 Set-1

A rigid uniform rod AB of length L and mass m is hinged at C such that AC = L/3, CB = 2L/3. Ends A and B are supported by springs of spring constant k. The natural frequency of the system is given by

A

√(k/(2m))

B

√(k/m)

C

√(2k/(m))

D

√(5k/(m))



Ques 27 GATE 2013 SET-4

A single degree of freedom system having mass 1 kg and stiffness 10 kN/m initially at rest is subjected to an impulse force of magnitude 5 kN for 10-4 seconds. The amplitude in mm of the resulting free vibration is

A

0.5

B

1.0

C

5.0

D

10.0



Ques 28 GATE 2013 SET-3

A single degree of freedom system having mass 1 kg and stiffness 10 kN/m initially at rest is subjected to an impulse force of magnitude 5 kN for 10-4 seconds. The amplitude in mm of the resulting free vibration is

A

0.5

B

1.0

C

5.0

D

10.0