1. Which type of vibrations are also known as transient vibrations?
Correct : B. Damped vibrations
2. During transverse vibrations, shaft is subjected to which type of stresses?
Correct : C. Bending stresses
3. What are deterministic vibrations?
Correct : A. Vibrations caused due to known exciting force
4. Which of the following vibrations are classified according to magnitude of
actuating force?
Correct : B. Deterministic vibrations
5. In which type of vibrations, amplitude of vibration goes on decreasing every
cycle?
Correct : A. Damped vibrations
6. The resonant frequency of a mass-spring system depends upon ________
Correct : D. all of the above
7. Calculate equivalent stiffness of the spring for the system shown below,
which has spring stiffness of 3000 N/m
Correct : B. 2250 N/m
8. Which of the following is incorrect regarding inertia force?
Correct : D. Same direction as of accelerating force
9. D-Alembert’s principle is used for which of the following?
Correct : B. Change dynamic problem to static problem
10. Determine logarithmic decrement, if the amplitude of a vibrating body
reduces to 1/6th in two cycles.
Correct : B. 0.8958
11. Calculate logarithmic decrement if damping factor is 0.33.
Correct : D. 2.19
12. In damped free vibrations, which parameters indicate vibrations?
Correct : B. Rate of decay of amplitude
13. What is meant by critical damping coefficient?
Correct : B. The motion is aperiodic in nature
14. Which of the following relations is true for viscous damping?
Correct : B. Force α relative velocity
15. Which among the following is the value of static deflection (δ) for a fixed
beam with central point load?
Correct : A. (Wl3) /(192 EI)
16. According to which method, maximum kinetic energy at mean position is
equal to maximum potential energy at extreme position?
Correct : B. Rayleigh's method
17. The motion of a system executing harmonic motion with one natural
frequency is known as _______
Correct : C. both a. and b.
18. Fluid resistance causes damping which is known as ______
Correct : C. Viscous damping
19. In which direction does the accelerating force acts?
Correct : B. Along the motion
20. The time interval after which the motion is repeated itself is known as ___________ .
Correct : A. Time period
21. Frequency of vibrations is usually expressed in
Correct : C. Number of cycles per second
22. The motion completed during one time period is known as _______.
Correct : B. Cycle
23. Which of the following is a type of free vibration?
Correct : D. A, B and C
24. In a spring-mass system, which of the following force is not considered?
Correct : B. Damping force
25. The periodic time is given by _______.
Correct : B. 2 π / ω
26. The velocity of a particle moving with simple harmonic motion is _______ at
the mean position.
Correct : C. Maximum
27. The maximum acceleration of a particle moving with simple harmonic motion
is ____.
Correct : B. ω.r
28. At the mean position, the potential energy of the system is _______.
Correct : A. Zero
29. In a spring-mass-damper system, which of the following force is considered?
Correct : D. All of the above
30. Frequency is equal to ______.
Correct : B. 1/time period
31. When the body vibrates under the influence of external force, then the body
is said to be under ___________ .
Correct : C. Forced vibrations
32. A vertical spring-mass system has a mass of 0.5 kg and an initial deflection
of 0.2 cm. Find the spring stiffness.
Correct : D. 2452 N/m
33. A system has a mass of 0.5 kg and spring stiffness of 2452 N/m. Find the
natural frequency of the system.
Correct : C. 11.14 Hz
34. What is meant by node point?
Correct : C. The point at which amplitude of vibration is zero
35. The motion of a system executing harmonic motion with one
natural frequency is known as _______
Correct : C. both a. and b.
36. Which of the following statements is/are true?
Correct : A. Torsional vibrations do not occur in a three rotor system, if rotors rotate in same direction
37. In the diagram shown below, if rotor X and rotor Z rotate in
same direction and rotor Y rotates in opposite direction, then specify the type of node vibration.
Correct : B. Two node vibration
38. What is the total number of nodes formed in a three rotor system if
the rotors at one of the ends and the one in the middle rotate in the
Correct : B. 1
39. In a multi-rotor system of torsional vibration maximum number of nodes that can occur is:
Correct : D. Equal to the number of rotors minus one
40. During torsional vibration of a shaft, the node is characterized by
Correct : D. Zero angular displacement
41. The mass moment of inertia of the two motors in a two rotor system
are 100 kgm2 and 10 kgm2 the length of the shaft of uniform
Correct : C. 100 cm
42. What is the number of nodes in a shaft carrying three rotors?
Correct : B. 2
43. Consider the following statements: Two rotors mounted on a single shaft can be considered to be equivalent to a geared-shaft system having two rotors provided
1. The kinetic energy of the equivalent system is equal to that of the original system. 2. The strain energy of the equivalent system is equal to that of the original system. 3. The shaft diameters of the two systems are equal. Which of these statements are correct?
Correct : A. 1, 2 and 3
44. Two rotors A and B are connected to the two ends of a shaft of
uniform diameter. The mass moment of inertia of rotor A about the
Correct : A. 1/5 m
45. Which one of the following is correct for a shaft carrying two rotors
at its ends?
Correct : B. It has one node
46. A system, which is free from both the ends
Correct : B. Semidefinite system
47. A system, which is fixed from one end or both the ends is referred
as
Correct : A. Definite system
48. In a system with different shaft parameters, the longest shaft is
taken for calculations.
Correct : B. FALSE
49. In a system with different shaft parameters ------------- is taken
which depends on the length and diameters of each shaft.
Correct : A. Equivalent shaft length
50. From the following data, calculate the location of node from the left
end of shaft (l1).l1=0.6m, l2=0.5m, l3=0.4m d1=0.095m, d2=0.06m, d3=0.05m Ma = 900 Kg, Mb = 700 Kg ka = 0.85m, kb = 0.55m
Correct : A. 0.855m
51. For a vibration system having different shaft parameters, calculate
which of the following cannot be the diameter of the equivalent shaft if the diameters of shafts in m are: 0.05, 0.06, 0.07.
Correct : D. 0.08
52. A single cylinder oil engine works with a three rotor system, the shaft length is 2.5m and 70mm in diameter, the middle rotor is at a distance 1.5m from one end. Calculate the free torsional vibration frequency for a single node system in Hz if the mass moment of inertia of rotors in Kg-m2 are: 0.15, 0.3 and 0.09. C=84 kN/mm2
Correct : A. 171
53. At a nodal point in the shaft, the frequency of vibration is
_________
Correct : A. Zero
54. For a gearing system, the equivalent system is made consisting of two rotors. How many nodes will this new equivalent system will have?
Correct : B. 1
55. In a gearing system, pump speed is one third of the motor. Shaft from motor is 6 cm in diameter and 30cm long, the impellar shaft is 10cm diameter and 60cm long. Mass moment of inertia is 1500 Kgm2, C = 80Gn/m2. Neglecting the inertia of shaft and gears calculate the frequency of free torsional vibrations in Hz.
Correct : A. 4.7
56. When inertia of gearing is taken into consideration, then which of
the following should be taken into account.
Correct : A. Addition of rotor
57. Consider P and Q as the shaft having two rotors at the end of it,
what is the point N known as in the given figure?
Correct : A. Node
58. For occurrence of free torsional vibration which of the condition is
necessary?
Correct : B. Rotors having same frequency
59. n the given figure if N is the node then NQ acts as which of the
following system?
Correct : A. Single rotor system
60. Keeping the mass moment of inertia of both the shafts in a two rotor system same, if the length of one shaft is doubled what should be the effect on the length of other shaft?
Correct : A. Doubled
61. In the figure given below, the points N1 and N2 are known
as_______
Correct : A. Nodes
62. In which of the following condition torsional vibration will not take place, considering 3 rotors A, B and C. A is rotating in clockwise direction.
Correct : C. B and C in clockwise
63. For occurrence of free torsional vibration in a three rotor system
which of the condition is necessary?
Correct : B. Rotors having same frequency
64. A vertical circular disc is supported by a horizontal stepped shaft as shown below. Determine equivalent length of shaft when equivalent diameter is 20 mm.
Correct : B. 0.559 m
65. In a three rotor system, for the middle rotor, if the stiffness of both
the length either side of the rotor is increased to two times what will
Correct : C. Increases by two times
66. A single cylinder oil engine works with a three rotor system, the shaft length is 2.5m and 70mm in diameter, the middle rotor is at a distance 1.5m from one end. Calculate the free torsional vibration frequency for a two node system in Hz if the mass moment of inertia of rotors in Kg-m2 are: 0.15, 0.3 and 0.09. C=84 kN/mm2
Correct : D. 277
67. Increasing which of the following factor would result in increase of free torsional vibration?
Correct : C. Polar moment of inertia
68. The frequency of the free torsional vibration depends on…....
Correct : C. Both a and b
69. For a two rotor system, the mass moment of inertia of one shaft(A) is twice the
other(B), then what is the relation between the length of the shafts.
Correct : A. 2L(A) = L(B)
70. Which of the following is true for centrifugal force causing unbalance?
Correct : A. Direction changes with rotation
71. If the unbalanced system is not set right then.
Correct : A. Static forces develop
72. What is the effect of a rotating mass of a shaft on a system?
Correct : A. Bend the shaft
73. In a revolving rotor, the centrifugal force remains balanced as long as the
centre of the mass of the rotor lies ___________
Correct : B. On the axis of the shaft
74. Often an unbalance of forces is produced in rotary or reciprocating machinery
due to the ______
Correct : D. Inertia forces
75. The mass used to balance the mass defect is known as ______
Correct : A. Balancing mass
76. In balancing of single-cylinder engine, the rotating unbalance is ____________
Correct : B. completely made zero and the reciprocating unbalance is partially reduced
77. Let the disturbing mass be 100 kg and the radius of rotation be 10 cm and the
rotation speed be 50 rad/s, then calculate the centrifugal force in kN.
Correct : B. 25
78. Which of the following statement is correct?
Correct : C. In the case of balancing of multimass rotating systems, dynamic balancing can be directly started without static balancing done to the system
79. If all the masses are in one plane, then what is the maximum no. of masses
which can be placed in the same plane?
Correct : D. No limitation
80. Which of the following statements is correct about the balancing of a
mechanical system?
Correct : C. Both static as well as dynamic balance have to be achieved separately
81. In a locomotive, the ratio of the connecting rod length to the crank radius is
kept very large in order to
Correct : B. minimize the effect of secondary forces
82. Secondary forces in reciprocating mass on engine frame are
Correct : B. twice the frequency as of primary forces
83. For a V-twin engine, which of the following means can be used to balance the
primary forces?
Correct : A. Revolving balance mass
84. The primary unbalanced force is maximum when the angle of inclination of the
crank with the line of stroke is
Correct : C. 180°
85. From the following data of a 60 degree V-twin engine, determine the minimum value for primary forces in newtons:Reciprocating mass per cylinder = 1.5 Kg Stroke length = 10 cm Length of connecting rod = 25 cm Engine speed = 2500 rpm
Correct : C. 2570
86. From the following data of a 60 degree V-twin engine, determine the maximum value for primary forces in newtons:Reciprocating mass per cylinder = 1.5 Kg Stroke length = 10 cm Length of connecting rod = 25 cm Engine speed = 2500 rpm
Correct : A. 7711
87. In the given figure, m1=10 Kg, m2=30Kg and m=50 Kg, if r=0.3m, l=1m, find
l2 = 0.5m, find r1 in m.
Correct : B. 0.75
88. From the given data, find the balancing mass’s inclination in degrees if r=0.2m required in the same plane.Masses = 200kg, 300kg, 240 kg, 260Kg,
Correct : A. 201.48
89. Which of the following statements are associated with complete dynamic balancing of rotating systems? 1. Resultant couple
due to all inertia forces is zero. 2. Support reactions due to forces are zero but not due to couples . 3. The system is automatically statically balanced. 4. Centre of masses of the system lies on the axis of rotation.
Correct : D. 1, 3 and 4 only
90. A V-twin engine has the cylinder axes at 90 degrees and the connecting rods operate a common crank. The reciprocating mass per cylinder is 11.5 kg and the crank radius is 7.5 cm. The length of the connecting rod is 0.3 m. If the engine is rotating at the speed is 500 r.p.m. What is the value of maximum resultant secondary force in Newtons?
Correct : B. 836
91. Let the centrifugal force in kN be 25 and the radius of rotation be 20 cm and
the rotation speed be 50 rad/s, then calculate the mass defect in Kg.
Correct : A. 50
92. In a multicylinder inline engine, each imaginary secondary crank with a mass
attached to the crankpin is inclined to the line of stroke at which angle?
Correct : A. Twice the angle of crank
93. In order to achieve stability, the sum of secondary forces and secondary
couples must be ------- and their respective polygons must be …......
Correct : A. Zero, Closed
94. For the secondary balancing of the engine, which of the condition is necessary?
Correct : A. Secondary force polygon must be close
95. The numerical values of the secondary forces and secondary couples couples
may be obtained by considering the ___________
Correct : A. Revolving mass
96. Which of the following is the correct expression for secondary force?
Correct : A. m𝜔^2r.cos2θ/n
97. A V-twin engine has the cylinder axes at 90 degrees and the connecting rods operate a common crank. The reciprocating mass per cylinder is 23 kg and the crank radius is 7.5 cm. The length of the connecting rod is 0.3 m. If the engine is rotating at the speed is 500 r.p.m. What is the value of maximum resultant secondary force in Newtons?
Correct : B. 1672
98. A V-twin engine has the cylinder axes at 90 degrees and the connecting rods operate a common crank. The reciprocating mass per cylinder is 34.5 kg and the crank radius is 7.5 cm. The length of the connecting rod is 0.3 m. If the engine is rotating at the speed is 500 r.p.m. What is the value of maximum resultant secondary force in kN?
Correct : B. 2.508
99. From the given data, find the balancing mass in Kg if r=0.2m required in the same plane.Masses = 200kg, 300kg, 240 kg, 260Kg, corresponding radii = 0.2m, 0.15m, 0.25m and 0.3m.Angles between consecutive masses = 45, 75 and 135 degrees.
Correct : A. 116
100. Let the disturbing mass be 200 kg and the radius of rotation be 20 cm and the
rotation speed be 50 rad/s, then calculate the centripetal force in kN.