1) Calculate damped natural frequency, if a spring mass damper system is subjected to periodic disturbing force of 30 N. Damping coefficient is equal to 0.76 times of critical damping coefficient and undamped natural frequency is 5 rad/sec
a. 3.99 rad/sec
b. 2.13 rad/sec
c. 4.12 rad/sec
d. 3.24 rad/sec
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Answer
Explanation
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ANSWER: 3.24 rad/sec
Explanation:
No explanation is available for this question!
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2) Calculate critical speed of a vehicle which moves on a road having sinusoidal profile of wavelength 2.5 m. The mass of the vehicle is 300 kg and natural frequency of its spring suspension system is 8 rad/sec
a. 4.15 m/sec
b. 3.18 m/sec
c. 2.36 m/sec
d. None of the above
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Answer
Explanation
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ANSWER: 3.18 m/sec
Explanation:
No explanation is available for this question!
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3) What is the effect of damping on phase angle at resonance frequency?
a. Phase angle increases as damping increases
b. Damping has no effect on phase angle
c. Phase angle increases as damping decreases
d. None of the above
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Answer
Explanation
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ANSWER: Damping has no effect on phase angle
Explanation:
No explanation is available for this question!
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4) When frequency ratio (ω/ωn) is greater than unity, phase angle decreases as ______
a. damping factor increases
b. damping factor decreases
c. both a. and b.
d. none of the above
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Answer
Explanation
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ANSWER: damping factor increases
Explanation:
No explanation is available for this question!
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5) At which frequency ratio, phase angle increases as damping factor increases?
a. When frequency ratio is less than unity
b. When frequency ratio is more than unity
c. When frequency ratio is zero
d. All of the above
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Answer
Explanation
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ANSWER: When frequency ratio is less than unity
Explanation:
No explanation is available for this question!
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6) Which of the following statements is/are true?
1. Magnification factor is minimum at resonance
2. The maximum value of amplification factor increases as damping factor decreases
3. The maximum value of amplification factor increases as damping factor increases
4. Magnification factor is maximum at resonance
a. Statement 1 and statement 2
b. Statements 1,2 and 3
c. Statement 2 and statement 4
d. All the above statements are true
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Answer
Explanation
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ANSWER: Statement 2 and statement 4
Explanation:
No explanation is available for this question!
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7) Magnification factor is the ratio of ______
a. zero frequency deflection and amplitude of steady state vibrations
b. amplitude of steady state vibrations and zero frequency deflection
c. amplitude of unsteady state vibrations and zero frequency distribution
d. none of the above
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Answer
Explanation
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ANSWER: amplitude of steady state vibrations and zero frequency deflection
Explanation:
No explanation is available for this question!
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8) Consider the steady-state absolute amplitude equation shown below, if ω / ωn = √2 then amplitude ratio (X/Y) =?
(X/Y) = √{1 + [ 2ξ (ω/ωn)]2} / √{[1 – (ω/ωn)2]2 + {2ξ (ω/ωn)2}
a. 0
b. 1
c. less than 1
d. greater than 1
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Answer
Explanation
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ANSWER: 1
Explanation:
No explanation is available for this question!
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9) What is meant by phase difference or phase angle in forced vibrations?
a. Difference between displacement vector (x p) and velocity vector V p
b. Angle in which displacement vector leads force vector by (F 0 sinωt)
c. Angle in which displacement vector (x p) lags force vector (F 0 sinωt)
d. None of the above
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Answer
Explanation
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ANSWER: Angle in which displacement vector (xp) lags force vector (F0 sinωt)
Explanation:
No explanation is available for this question!
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10) The equation m(d2x/ dt2) + c (dx/dt) + Kx = F0 sin ωt is a second order differential equation. The solution of this linear equation is given as
a. complementary function
b. particular function
c. sum of complementary and particular function
d. difference of complementary and particular function
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Answer
Explanation
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ANSWER: sum of complementary and particular function
Explanation:
No explanation is available for this question!
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