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Higher Study | Mechanical Vibrations

Forced Vibration Damped Free Vibration Undamped Free Vibration
Whirling speed of the shaft is the speed at which
A three rotor system has following number of natural frequencies.
When the elements on the surface of the shaft move along the circumference of the shaft, the vibrations are called:
When no external force acts on a body after giving it initial displacement, the vibration of the body under this conditions is also known as:
An undamped spring-mass system with mass m and spring stiffness k is shown in the figure. The natural frequency and natural period of this system are ω rad/s and T s, respectively. If the stiffness of the spring is doubled and the mass is halved, then the natural frequency and the natural period of the modified system, respectively, are
There are four samples P, Q, R and S with natural frequencies 64, 96, 128 and 250 Hz respectively. They are mounted on test setups for conducting vibration experiments. If a loud pure note of frequency 144 Hz is produced by some instrument, which of the samples will show the most perceptible induced vibration?
 A mass of 50 kg suspended from one end of a helical spring, the other end being fixed. The stiffness of the spring is 100 N/m. The resistance of air damping is given as 0.1 N/m/s vibrating freely at its natural frequency of 10 rad/s. What will be the magnification factor at resonance of the spring?
Which condition is suitable for indicating instruments in order to get the best results?
The Smallest and largest natural frequencies of a 'n' degree freedom system are ω1 and ωn respectively. The approximate natural frequency estimated by Rayleigh’s and Dankerley’s methods is ωr and ωd respectively. Which of the following statements is true?
Which of the following are responsible for occurrence of critical or whirling speed of shaft?  1. Eccentric mounting of the rotor 2. Non-uniform distribution of rotor material 3. Bending of shaft due to the weight of the rotor and the shaft itself 4. Environmental effect such as effect of moisture and temperature Select the correct answer using the code given below.
Which of the following relationships between the force F on a particle and the particles position x implies simple harmonic oscillation
When the frequency of the vibrating system becomes equal to the natural frequency of the system, this type of vibration is known as:
Consider the following statements. Transmissibility of vibrations (1) Is more than 1, when ω/ωn < √2  (2) Is less than 1, when ω/ωn > √2  (3) Increases as the damping is increased
When a system is subjected to forced vibrations, then under steady-state conditions
Damping is beneficial only when:
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