1) A vibrating machine of 100 kg is mounted on a rubber pad which has stiffness of 500 N/m. Determine force transmitted to the foundation if the unbalanced force 500 N acts on it. The frequency ratio (ω/ωn) is 1.5 and ξ = 0.5
a. 461.62 N
b. 400.23 N
c. 450 N
d. Insufficient data
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Answer
Explanation
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ANSWER: 461.62 N
Explanation:
No explanation is available for this question!
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2) Which of the following statements is/are false for pneumatic isolators ?
1. Pneumatic isolators are used when driving frequencies below 10 Hz are present
2. Nausea is caused due to noise at low frequencies
3. At high natural frequencies, isolators can obtain efficiency of 90%
4. Pneumatic isolators have limited load carrying capacity
a. Only statement 1
b. Only statement 3
c. Only statement 2, 4
d. All the above statements are false
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Answer
Explanation
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ANSWER: Only statement 3
Explanation:
No explanation is available for this question!
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3) Which of the following statements is/are true for elastomers?
a. Elastomers can be used for static deflections up to 12 mm
b. Elastomers can provide natural frequencies below 5 Hz
c. Elastomers have good performance at high frequencies
d. All the above statements are true
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Answer
Explanation
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ANSWER: All the above statements are true
Explanation:
No explanation is available for this question!
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4) Transmissibility is the ratio of ______
a. force transmitted to the supporting structure and force impressed upon the system
b. displacement amplitude of mass and displacement amplitude of supporting structure
c. both a. and b.
d. none of the above
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Answer
Explanation
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ANSWER: both a. and b.
Explanation:
No explanation is available for this question!
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5) What is the function of the controller in active vibration isolation systems?
a. Detect vibrations to be controlled
b. Reposition the masses
c. Interpret detected vibrations and execute commands
d. All of the above
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Answer
Explanation
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ANSWER: Interpret detected vibrations and execute commands
Explanation:
No explanation is available for this question!
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6) Which among the following is not considered when reference standards are used in the field of mechanical vibration and shock, monitoring and analysis of machines?
a. Terminology
b. Methods of testing
c. Methods of measurement
d. None of the above
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Answer
Explanation
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ANSWER: None of the above
Explanation:
No explanation is available for this question!
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7) Which basic document describes general requirements for measurement and evaluation of machine vibrations using shaft measurements?
a. ISO – 10816-1
b. ISO – 7919-1
c. Both a. and b.
d. None of the above
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Answer
Explanation
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ANSWER: ISO – 7919-1
Explanation:
No explanation is available for this question!
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8) In the graph shown below, the region in which frequency ratio (ω/ωn) > √2 is known as____
a. Amplification region
b. Isolation region
c. Spring controlled region
d. None of the above
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Answer
Explanation
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ANSWER: Isolation region
Explanation:
No explanation is available for this question!
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9) Which of the following is a type of untuned vibration absorber?
a. Houdaille damper
b. Torsional vibration absorber
c. Centrifugal pendulum absorber
d. All of the above
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Answer
Explanation
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ANSWER: Houdaille damper
Explanation:
No explanation is available for this question!
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10) Which of the following methods can be used to reduce excitation level at the source?
a. Lubrication of joints
b. Balancing inertia forces
c. Both a. and b.
d. None of the above
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Answer
Explanation
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ANSWER: Both a. and b.
Explanation:
No explanation is available for this question!
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