McqMate
Chapters
| 1. |
What is meant by node point? |
| A. | The point at which amplitude of vibration is maximum |
| B. | The point at which amplitude of vibration is minimum |
| C. | The point at which amplitude of vibration is zero |
| D. | None of the above |
| Answer» C. The point at which amplitude of vibration is zero | |
| 2. |
The motion of a system executing harmonic motion with one natural frequency is known as _______ |
| A. | principal mode of vibration |
| B. | natural mode of vibration |
| C. | both a. and b. |
| D. | none of the above |
| Answer» C. both a. and b. | |
| 3. |
Which of the following statements is/are true? |
| A. | Torsional vibrations do not occur in a three rotor system, if rotors rotate in same direction |
| B. | Shaft vibrates with maximum frequency when rotors rotate in same direction |
| C. | Zero node behavior is observed in rotors rotating in opposite direction |
| D. | All of the above |
| Answer» A. Torsional vibrations do not occur in a three rotor system, if rotors rotate in same direction | |
| 4. |
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. |
| A. | Three node vibration |
| B. | Two node vibration |
| C. | Single node vibration |
| D. | None of the above |
| Answer» B. Two node vibration | |
| 5. |
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 |
| A. | 0 |
| B. | 1 |
| C. | 2 |
| D. | 3 |
| Answer» B. 1 | |
| 6. |
In a multi-rotor system of torsional vibration maximum number of nodes that can occur is: |
| A. | Two |
| B. | Equal to the number of rotor plus one |
| C. | Equal to the number of rotors |
| D. | Equal to the number of rotors minus one |
| Answer» D. Equal to the number of rotors minus one | |
| 7. |
During torsional vibration of a shaft, the node is characterized by |
| A. | Maximum angular velocity |
| B. | Maximum angular displacement |
| C. | Maximum angular acceleration |
| D. | Zero angular displacement |
| Answer» D. Zero angular displacement | |
| 8. |
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 |
| A. | 80 cm |
| B. | 90 cm |
| C. | 100 cm |
| D. | 110 cm |
| Answer» C. 100 cm | |
| 9. |
What is the number of nodes in a shaft carrying three rotors? |
| A. | zero |
| B. | 2 |
| C. | 3 |
| D. | 4 |
| Answer» B. 2 | |
| 10. |
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? |
| A. | 1, 2 and 3 |
| B. | 1 and 2 |
| C. | 2 and 3 |
| D. | 1 and 3 |
| Answer» A. 1, 2 and 3 | |
| 11. |
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 |
| A. | 1/5 m |
| B. | 4/5 m |
| C. | 1/25 m |
| D. | 16/25 m |
| Answer» A. 1/5 m | |
| 12. |
Which one of the following is correct for a shaft carrying two rotors at its ends? |
| A. | It has no node |
| B. | It has one node |
| C. | It has two nodes |
| D. | It has three nodes |
| Answer» B. It has one node | |
| 13. |
A system, which is free from both the ends |
| A. | Definite system |
| B. | Semidefinite system |
| C. | Both a and b |
| D. | None of the above |
| Answer» B. Semidefinite system | |
| 14. |
A system, which is fixed from one end or both the ends is referred as |
| A. | Definite system |
| B. | Semidefinite system |
| C. | Both a and b |
| D. | None of the above |
| Answer» A. Definite system | |
| 15. |
In a system with different shaft parameters, the longest shaft is taken for calculations. |
| A. | TRUE |
| B. | FALSE |
| Answer» B. FALSE | |
| 16. |
In a system with different shaft parameters ------------- is taken which depends on the length and diameters of each shaft. |
| A. | Equivalent shaft length |
| B. | length of first shaft |
| C. | lrngth of intermediate shaft |
| D. | None of these |
| Answer» A. Equivalent shaft length | |
| 17. |
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 |
| A. | 0.855m |
| B. | 0.795m |
| C. | 0.695m |
| D. | 0.595m |
| Answer» A. 0.855m | |
| 18. |
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. |
| A. | 0.05 |
| B. | 0.06 |
| C. | 0.07 |
| D. | 0.08 |
| Answer» D. 0.08 | |
| 19. |
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 |
| A. | 171 |
| B. | 181 |
| C. | 191 |
| D. | 201 |
| Answer» A. 171 | |
| 20. |
At a nodal point in the shaft, the frequency of vibration is _________ |
| A. | Zero |
| B. | Double than at the ends |
| C. | Minimum |
| D. | Maximum |
| Answer» A. Zero | |
| 21. |
For a gearing system, the equivalent system is made consisting of two rotors. How many nodes will this new equivalent system will have? |
| A. | 0 |
| B. | 1 |
| C. | 2 |
| D. | 3 |
| Answer» B. 1 | |
| 22. |
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. |
| A. | 4.7 |
| B. | 5.7 |
| C. | 4.5 |
| D. | 5.5 |
| Answer» A. 4.7 | |
| 23. |
When inertia of gearing is taken into consideration, then which of the following should be taken into account. |
| A. | Addition of rotor |
| B. | Addition of gear |
| C. | Addition of shaft |
| D. | Addition of pump |
| Answer» A. Addition of rotor | |
| 24. |
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? |
| A. | Node |
| B. | Elastic point |
| C. | Inelastic point |
| D. | Breaking point |
| Answer» A. Node | |
| 25. |
For occurrence of free torsional vibration which of the condition is necessary? |
| A. | Rotors moving in same direction |
| B. | Rotors having same frequency |
| C. | Rotors having different frequency |
| D. | Rotors rotate in the same sense |
| Answer» B. Rotors having same frequency | |
| 26. |
n the given figure if N is the node then NQ acts as which of the following system? |
| A. | Single rotor system |
| B. | Two rotor system |
| C. | Three rotor system |
| D. | Four rotor system |
| Answer» A. Single rotor system | |
| 27. |
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? |
| A. | Doubled |
| B. | Halved |
| C. | Constant |
| D. | increased to 4 times |
| Answer» A. Doubled | |
| 28. |
In the figure given below, the points N1 and N2 are known as_______ |
| A. | Nodes |
| B. | Elastic points |
| C. | Inelastic points |
| D. | Breaking points |
| Answer» A. Nodes | |
| 29. |
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. |
| A. | B in clockwise C in anticlockwise |
| B. | C in clockwise B in anticlockwise |
| C. | B and C in clockwise |
| D. | B and C in anticlockwise |
| Answer» C. B and C in clockwise | |
| 30. |
For occurrence of free torsional vibration in a three rotor system which of the condition is necessary? |
| A. | Rotors moving in same direction |
| B. | Rotors having same frequency |
| C. | Rotors having different frequency |
| D. | Rotors rotate in the same sense |
| Answer» B. Rotors having same frequency | |
| 31. |
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. |
| A. | 1.559 m |
| B. | 0.559 m |
| C. | 0.633 m |
| D. | None of the above |
| Answer» B. 0.559 m | |
| 32. |
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 |
| A. | Remains constant |
| B. | Decreases by two times |
| C. | Increases by two times |
| D. | Increases by 4 times |
| Answer» C. Increases by two times | |
| 33. |
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 |
| A. | 257 |
| B. | 281 |
| C. | 197 |
| D. | 277 |
| Answer» D. 277 | |
| 34. |
Increasing which of the following factor would result in increase of free torsional vibration? |
| A. | Radius of gyration |
| B. | Mass moment of inertia |
| C. | Polar moment of inertia |
| D. | Length |
| Answer» C. Polar moment of inertia | |
| 35. |
The frequency of the free torsional vibration depends on….... |
| A. | number of rotors |
| B. | the number of nodes |
| C. | Both a and b |
| D. | Only b |
| Answer» C. Both a and b | |
| 36. |
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. |
| A. | 2L(A) = L(B) |
| B. | L(A) = 2L(B) |
| C. | L(A) = L(B) |
| D. | 2L(A) = 3L(B) |
| Answer» A. 2L(A) = L(B) | |
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