Quiznetik

Design of Machine Elements | Set 1

1. Stressed parts are always kept in tension.

Correct : A. true

2. Which process allows controlling grain structure of the product?

Correct : B. forging

3. Cast surfaces have good finishing.

Correct : B. false

4. In forging, metal is in which of the following stage?

Correct : B. plastic

5. Among casting, forging and forging which has the slowest rate of production?

Correct : C. machining

6. In manual assembly, cost of screw is higher than the cost of driving a screw.

Correct : B. false

7. Maximum carbon content in welding is usually limited to

Correct : A. 0.22%

8. Why tolerances are given to the parts?

Correct : A. because it’s impossible to make perfect settings

9. What is bilateral tolerance?

Correct : B. total tolerance is in both the directions

10. What is mean clearance?

Correct : C. mean size of hole minus mean size of shaft

11. Which of the following is incorrect about tolerances?

Correct : A. too loose tolerance results in less cost

12. Quality control charts doesn’t depend on which factor?

Correct : D. binomial distribution

13. If a clearance fit is present between shaft and hole, what is the tolerance on shaft or hole for a complete interchangeable approach?

Correct : A. ½ of maximum clearance – ½ of minimum clearance

14. A beam is said to be of uniform strength, if

Correct : D. bending stress is the same at every section along its longitudinal axis

15. Stress in a beam due to simple bending is

Correct : A. directly proportional

16. Which stress comes when there is an eccentric load applied?

Correct : B. bending stress

17. On bending of a beam, which is the layer which is neither elongated nor shortened?

Correct : B. neutral axis

18. The bending stress is

Correct : A. directly proportional to the distance of layer from the neutral layer

19. Consider a 250mmx15mmx10mm steel bar which is free to expand is heated from 15C to 40C. what will be developed?

Correct : D. no stress

20. The safe stress for a hollow steel column which carries an axial load of 2100 kN is 125 MN/m2. if the external diameter of the column is 30cm, what will be the internal diameter?

Correct : B. 26.19cm

21. Stress intensity factor is the critical value of stress at which crack extension occurs.

Correct : B. false

22. Fracture toughness does not depend upon geometry of the part containing crack

Correct : B. false

23. How many modes are there for crack propagation?

Correct : B. 3

24. A curved beam has neutral axis is curved while loaded and straight when unloaded.

Correct : B. false

25. The bending stress in a straight beam varies linearly with the distance from neural axis like that in a curved beam.

Correct : B. false

26. 1816mm and radius of centroidal axis is 100mm, then find the bending stress at inner fibre whose radius is 50mm. Area of cross section of beam is 7200mm² and the beam is loaded with 100kN of load.

Correct : C. 100.6

27. 1816/ [7200 x 10.8184 x 50] or σ=100.6N/mm².

Correct : B. 13.95mm

28. A curved beam with eccentricity 0.02D is loaded with 1kN.Centroidal radius=4D and inner and outer radii are 3.5D and 4.5D respectively. Area of cross section is 0.8D². Find the dimension D if allowable stress is 110N/mm² and considering only direct tensile stress.

Correct : D. 3.4mm

29. All type of stresses vanishes after as soon as the applied load is removed.

Correct : B. false

30. Residual stresses are always added in the load stresses and hence are always harmful.

Correct : B. false

31. Which of the following is the numerator of factor safety formula?

Correct : D. ultimate stress

32. Which of the following can be the factor of safety for shock loading?

Correct : B. 13

33. Factor of safety is used to find out the reliability of the design.

Correct : A. true

34. What can understand by the factor of safety equal to one?

Correct : B. it means that the structure will only support the actual load

35. For which of the following design factor of

Correct : C. 2

36. What is a safe factor of failure for a component which on failure can result in financial loss or serious injury?

Correct : D. 4

37. Design factor for most aircraft structures is 2.

Correct : B. false

38. Does ASME Standard take into consideration shock and fatigue factors?

Correct : A. yes

39. Calculate the tension in the rope of pulley C. "The layout of a shaft supported on bearings at A & B is shown. Power is supplied by means of a vertical belt on pulley B which is then transmitted to pulley C carrying a horizontal belt. The angle of wrap is 180’ and coefficient of friction is 0.3. Maximum permissible tension in the rope is 3kN. The radius of pulley at B & C is 300mm and 150mm"

Correct : B. 5948.15n and 2288.75n

40. If bending moment on point B in horizontal plate is M and in vertical plane is m, then the net bending moment at point B is? "The layout of a shaft supported on bearings at A & B is shown. Power is supplied by means of a vertical belt on pulley B which is then transmitted to pulley C carrying a horizontal belt. The angle of wrap is 180’ and coefficient of friction is 0.3. Maximum permissible tension in the rope is 3kN. The radius of pulley at B & C is 300mm and 150mm"

Correct : D. √m²+m²

41. If yielding strength=400N/mm², the find the permissible shear stress according to ASME standards.

Correct : A. 72 n/mm²

42. The strength of hollow shaft is more than the strength of solid shaft of same weight.

Correct : A. true

43. Solid shafts are used in epicyclic gearboxes.

Correct : B. false

44. Refer to fig Two plates are fastened by means of two bolts. The yield strength of bolt is 400N/mm² and factor of safety is 4. Determine the size of the bolts.

Correct : A. 8mm

45. 8’CW from the vertical. Hence net shear force = √ [5000cos36.8+1250]²+ [5000sin36.8]².

Correct : A. 10.74mm

46. Which bolt is under maximum shear stress?

Correct : C. 3

47. Arrange the bolts in order of decreasing shear stresses.

Correct : D. 3>2>1

48. Determine the size of the bolts if yield strength of bolt is 400N/mm² and factor of safety is 4. The bolts are equidistant having separated by 60mm and the margin to the left and right is 25mm. Also P=5kN acts at a distance of 200mm from the channel.

Correct : B. 13.44mm

49. A knuckle joint is unsuitable for two rotating shafts, which transmit torque

Correct : A. true

50. A maximum of how many roads may be connected using a knuckle joint?

Correct : B. 3

51. Which of the following are important parts of knuckle joint?

Correct : D. each of the mentioned

52. Calculate the diameter of pin from shear consideration with maximum shear stress allowed is 40NN/mm² and an axial tensile force of 50kN is acting on the rod.

Correct : A. 39mm

53. A knuckle joint can be used in valve mechanism of a reciprocating engine.

Correct : A. yes

54. Cotter joint is used when the members are subjected to which type of stresses?

Correct : C. axial tensile or compressive

55. The principle of wedge action is used in cotter joint.

Correct : A. true

56. Which of the following is not a part of cotter joint?

Correct : D. collar

57. Cold riveting holds the connected parts better than hot riveting.

Correct : B. false

58. 67 N/mm².; Spigot dia=65mm; thickness 0f collar=15mm

Correct : A. 131mm

59. Cotter joint can be used to connect two rods for torque transmission purpose.

Correct : B. false

60. Thickness of plate is required more in welding than in riveting.

Correct : B. false

61. The capacity of welded structures to damp vibrations is quite good.

Correct : B. false

62. Themit consists of a finely divided mixture of iron oxide and copper.

Correct : B. false

63. Rails in the field are generally welded by using

Correct : A. thermit welding

64. In gas welding which of the following is generally used?

Correct : C. oxygen-hydrogen or oxygen-acetylene

65. Filler material is used in electric resistance welding.

Correct : B. no filler material used

66. Which type of welding is generally used in automobile sector?

Correct : B. electric resistance welding

67. Hard peening is

Correct : B. hammering the weld along the length while the joint is hot

68. A rivet is specified as a 20mm rivet. What does it mean?

Correct : B. shank dia 20mm

69. In hand riveting die is a part of hammer.

Correct : B. false

70. The amount by which the two rods to be joined are drawn together is called as?

Correct : A. draw

71. Two steel rods connected by cotter joint are subjected to 50 kN load each. What is the minimum diameter required of the rods? (Given: Yielding Stress= 400N/mm² ; Factor of Safety=6)

Correct : A. 31mm

72. Among punching and drilling, which is cheaper?

Correct : A. punching

73. Riveting is not recommended for aluminium alloys.

Correct : B. false

74. In joining steel plate and asbestos, welding is preferred over riveting.

Correct : B. false

75. Quality checking of riveted joint is much expensive than that of welded joint.

Correct : B. false

76. In which of the following bonding theory, water molecules break down to form H+ and OH- ions?

Correct : A. electrostatic bonding theory

77. What does the clay particle absorb in electrostatic bonding theory?

Correct : C. oh–ions

78. For bonding action of clays, what is the amount of water needed?

Correct : A. 1.5%-8%

79. What is the amount of sea coal needed in cast irons for large green casting moulding sands?

Correct : A. 10%

80. Pitch maybe used up to what percent?

Correct : B. 2%

81. Which of the following increases the dry strength of the sand?

Correct : D. dextrin and molasses

82. Cereals improve flowability and lower collapsibility.

Correct : B. false

83. How much should fuel oil be added to increase the moulding ability of sand?

Correct : A. 0.01% – 0.1%

84. Which of the following function can the spring perform?

Correct : D. all of the mentioned

85. The helix angle is very small about 2⁰. The spring is open coiled spring.

Correct : B. it is closed coiled spring

86. The helical spring ad wire of helical torsion spring, both are subjected to torsional shear stresses.

Correct : B. false

87. Multi leaf springs are not recommended for automobile and rail road suspensions.

Correct : B. false

88. The spring index is the ratio of wire diameter to mean coil diameter.

Correct : A. true

89. If spring index=2.5, what can be concluded about stresses in the wire?

Correct : A. they are high

90. A spring with index=15 is prone to buckling.

Correct : A. true

91. If number of coils are 8 and wire diameter of spring 3mm, then solid length is given by?

Correct : C. 24mm

92. Compressed length is smaller than the solid length.

Correct : B. false

93. Pitch of coil is defined as axial distance in compressed state of the coil.

Correct : B. it is measured in uncompressed state

94. The maximum fluctuation of speed is the

Correct : B. difference of the maximum and minimum speeds

95. In a turning moment diagram, the variations of energy above and below the mean resisting torque line is called

Correct : A. fluctuation of energy

96. The ratio of the maximum fluctuation of energy to the ……. is called coefficient of fluctuation of energy.

Correct : B. workdone per cycle

97. Due to the centrifugal force acting on the rim, the flywheel arms will be subjected to

Correct : A. tensile stress

98. The cross-section of the flywheel arms is usually

Correct : A. elliptical

99. In order to find the maximum bending moment on the arms, it is assumed as a

Correct : C. cantilever beam fixed at the hub and carrying a concentrated load at the free end of the rim

100. The diameter of the hub of the flywheel is usually taken

Correct : B. twice the diameter of the shaft