BME Dynamics and Vibrations 2

Question 1

The transmissibility ratio in vibration isolation is less than 1 when the frequency ratio (r = ω/ωn) is:

Accepted Answer

r > √2

Answer

Vibration isolation is effective (transmissibility < 1) only when the excitation frequency exceeds √2 times the natural frequency of the isolator.

Question 2

For a rotating unbalance, the centrifugal force causing vibration is proportional to:

Accepted Answer

Unbalance mass × eccentricity × ω²

Answer

The centrifugal force from a rotating unbalance is F = meω², where m is unbalance mass, e is eccentricity, and ω is angular speed.

Question 3

The work-energy theorem states that the net work done on a particle equals:

Accepted Answer

Change in kinetic energy

Answer

The work-energy theorem states that the net work done equals the change in kinetic energy: W_net = ΔKE = ½mv₂² - ½mv₁².

Question 4

A Fourier series is used in vibration analysis to:

Accepted Answer

Decompose periodic excitation into harmonic components

Answer

A periodic forcing function can be decomposed into sinusoidal harmonics using Fourier series, allowing response to each harmonic to be analyzed separately.

Question 5

In a two-degree-of-freedom system, the number of natural frequencies equals:

Accepted Answer

2

Answer

A system with n degrees of freedom has exactly n natural frequencies (and n corresponding mode shapes).

BME - Bachelor of Mechanical Engineering Practice Test

BME - Bachelor of Mechanical Engineering Practice Test

BME Dynamics and Vibrations 2