Explore topic-wise MCQs in Mechanical Vibrations.

This section includes 12 Mcqs, each offering curated multiple-choice questions to sharpen your Mechanical Vibrations knowledge and support exam preparation. Choose a topic below to get started.

1.

Damping force per unit velocity is known as

A. Damping factor
B. Damping coefficient
C. Logarithmic decrement
D. Stiffness of the spring
Answer» C. Logarithmic decrement
Discussion
2.

A vehicle suspension system consists of a leaf spring and a damper. The stiffness of the leaf spring is 3.6 kN/m and damping constant of the damper is 400 Ns/m. If the mass is 50 kg, then the damping factor and damped natural frequency respectively are

A. 0.471 and 1.19 Hz
B. 0.471 and 7.48 Hz
C. 0.666 and 1.35 Hz
D. 0.666 and 8.50 Hz
Answer» B. 0.471 and 7.48 Hz
Discussion
3.

In a spring dash pot, mass system if m = mass, k = spring stiffness and ωn = natural frequency of vibration, then critical damping is equal to

A. \(2\sqrt {km} \)
B. 2 m⋅ωn
C. both 1) and 2)
D. neither 1) nor 2)
Answer» D. neither 1) nor 2)
Discussion
4.

Damping is beneficial only when:

A. \(\frac{\omega }{{{\omega _n}}} = 1\)
B. \(\frac{\omega }{{{\omega _n}}} < 1\)
C. \(\frac{\omega }{{{\omega _n}}} < \sqrt2\)
D. \(\frac{\omega }{{{\omega _n}}} > \sqrt 2\)
Answer» D. \(\frac{\omega }{{{\omega _n}}} > \sqrt 2\)
Discussion
5.

A mass of 1 kg is attached to the end of a spring with stiffness 0.9 N/mm. The critical damping coefficient of this system is ____.

A. 1.40 Ns/m
B. 2 Ns/m
C. 60 Ns/m
D. 6 Ns/m
Answer» D. 6 Ns/m
Discussion
6.

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
Answer» C. Largest amount of damping for which the motion is simple harmonic in free vibration
Discussion
7.

Logarithmic decrement of a damped single degree of freedom system is δ. If stiffness of the spring is doubled and mass is made half, then logarithmic decrement of the new system will be equal to

A. 1/2δ
B. δ
C. 2δ
D. 1/4 δ
Answer» C. 2δ
Discussion
8.

A machine component of natural frequency 20 rad/s is subjected to a base motion from the machine which is harmonic in nature with acceleration of 3 m/s2 at 10 rad/s. What is the peak amplitude of relative displacement of the components if the damping is negligible?

A. 0.1 mm
B. 1.0 mm
C. 10.0 mm
D. 100.0 mm
Answer» D. 100.0 mm
Discussion
9.

Critical damping is a function of _________.

A. Mass and stiffness
B. Mass and damping co - efficient
C. Stiffness and natural frequency
D. Natural frequency and damping co - efficient
Answer» B. Mass and damping co - efficient
Discussion
10.

In an underdamped vibration system, logarithmic decrement is given by:

A. \( \frac{{2\pi \xi }}{{\sqrt {1 - {\xi ^2}} \;}}\)
B. \( \frac{{2\pi \xi^2 }}{{\sqrt {1 - {\xi ^2}} \;}}\)
C. \( \frac{{2\pi \xi }}{{\sqrt {1 + {\xi ^2}} \;}}\)
D. \( \frac{{2\pi \xi }}{{\sqrt {1 - {\xi }} \;}}\)
Answer» B. \( \frac{{2\pi \xi^2 }}{{\sqrt {1 - {\xi ^2}} \;}}\)
Discussion
11.

In a damped free vibration of a mass supported on a spring and a damper, where the damping force is proportional to the velocity, the ratio of two successive amplitudes

A. remains constant
B. gradually decreases and varies linearly with time
C. gradually decreases and varies exponentially with time
D. None of the above
Answer» B. gradually decreases and varies linearly with time
Discussion
12.

In the under-damped vibrating system, the amplitude of vibration with reference to time _____.

A. Increases linearly
B. Increases exponentially
C. Decreases linearly
D. Decreases exponentially
Answer» E.
Discussion