Quiznetik

Theory of Machines | Set 2

1. In case of V-belts

Correct : B. Belts should touch the bottom of groove in pulley

2. According to the law of gearing

Correct : C. Common normal at the point of contact always passes through a fixed point (pitch point) on the line joining the centres of rotation

3. In a V-belt having B section may be used when the load to be transmitted is

Correct : B. 3 to 20 HP

4. A slider crank chain consists of

Correct : C. Three turning and one sliding pairs

5. In case of reciprocating engines the primary forces

Correct : C. Are partially balanced

6. Which one of the following is a transmission type dynamometer?

Correct : E. None of the above

7. In case of gears the addendum is given by

Correct : E. One module

8. The rectilinear motion of a piston is converted into rotary motion by

Correct : C. Connecting rod

9. In case of gears the pressure angle is

Correct : A. The angle between the line of action and the common tangent to the pitch surface in the plane of rotation

10. A swinging pendulum in its mid-position possesses

Correct : B. only the kinetic energy

11. When the two elements of a pair are kept in contact with the help of a spring, the pair is known as

Correct : D. an unclosed pair

12. Which one of the following is a higher pair?

Correct : A. Tooth gearing mechanism

13. The difference between a machine and a structure is

Correct : B. The machine serves to modify and transmit mechanical work whereas structures serve to modify and transmit forces only

14. In case of lower pairs

Correct : A. There is surface contact between the two elements while in the motion

15. A 0.5 kg weight attached to a light spring elongates it 0.6 mm. The natural frequency of the system should be approximately

Correct : E. 16 Hz

16. A piston and cylinder in a slider crank mechanism form a

Correct : D. Sliding pair

17. In case of reciprocating engine mechanism

Correct : D. The primary force has twoce the frequency of secondary force

18. At node of the shaft

Correct : D. The vibrations are zero

19. In a well greased ball bearing the coefficient of friction may be in the range

Correct : E. 0.1 to 0.25

20. A vibrating system with unity as damping factor will be

Correct : E. Critically damped

21. In case of spur gears the flank of the tooth is

Correct : B. The part of the tooth surface lying below the pitch surface

22. The number of links in a pantograph is equal to

Correct : B. 4

23. Module is expressed in

Correct : A. mm

24. In case of an elliptical trammel

Correct : E. Two pairs turn and two pairs slide

25. Creep in belts is due to

Correct : D. Differential elougation of belt due to difference in tension on two sides of a pulley

26. Which one of the following is the inversion of slider crank mechanism

Correct : E. (A), (B) and (C) above

27. The radial depth of a ger tooth below the pitch circle is

Correct : E. Dedendum

28. The pitch point on a cam is

Correct : B. The point on cam pitch circle having the maximum pressure angle

29. While evaluating the minimum number of teeth on a opinion the major consideration is

Correct : C. To avoid interference

30. Gears of watches are generally manufactured by

Correct : A. Stamping

31. The effect of creep in case of cross belt drive is

Correct : C. to reduce the speed of driven pulley

32. Isochronism in a governor is desirable when

Correct : D. One speed is desired to be kept for all loads

33. In case of locomotives, the swaying couple is resisted by

Correct : E. (C) and (D) together

34. A gear cutter suitable for cutting 42 to 54 teeth will provide correct form

Correct : A. For any gear having teeth anywhere between 42 to 54

35. Sensitiveness of a governor is

Correct : D. The ratio of the difference between the maximum and minimum equilibrium speed to the mean equilibrium speed

36. A kinematic chain becomes a mechanism when

Correct : A. Any one link is fixed

37. Module for gear is expressed in terms of

Correct : C. Millimeters

38. Which is incorrect statement, if any

Correct : E. None of the above

39. In the cam mechanism, a mushroom follower is

Correct : B. One provided with a flat face with a perfect flat plane

40. In a slider-crank mechanism

Correct : A. there are 4 turning pairs

41. A nut and bolt form a

Correct : A. Helical pair

42. In case of meter gauge locomotives the distance between wheel centres is

Correct : B. 1 metre

43. Crowning is done on

Correct : C. Pulleys

44. In case of gears the tooth fillet is

Correct : B. Radius that connects the root circle to the profile of the tooth

45. The sense of tangential acceleration of a link

Correct : C. Could be either the same or opposite to velocity

46. A beater machine in a pulp mill is driven by a 50 H.P. motor using 6 vee belts of D section. If one of the belt breaks after a month

Correct : A. All the belts have to be replaced

47. A pantograph is a mechanism or a kinematic arrangement comprising

Correct : B. Two lower pairs

48. Which one of the following is lightest?

Correct : E. 1 US short ton

49. The angle of a V-belt is

Correct : D. 40?

50. A pantograph is a mechanism with

Correct : D. Lower pairs

51. In case of higher pairs

Correct : B. There is only line or point contact between the two elements while in motion

52. When one of the links of a kinematic chain is fixed it is known as

Correct : B. mechanism

53. Tan ? can be greater than

Correct : E. Tan ? can never be greater than

54. For a vibrating body, if ratio ?/?n is very high, then phase angle would tend to approach

Correct : C. 180?

55. Dynamically unbalanced masses in rotating machines cause

Correct : D. Vibrations

56. Which of the following are not standard forms for spur-gears?

Correct : A. All above

57. A stretched string of a guitar when operated is subjected to

Correct : C. Forced transverse vibrations

58. A vibrometer

Correct : C. Indicates vibration amplitude

59. For fluctuating loads, the appropriate bearing would be

Correct : E. Needle roller bearing

60. In case of belt drives, the effect of centrifugal tension is

Correct : A. To reduce the driving power

61. In case of instantaneous centre of rotation

Correct : D. The two rigid links have no linear velocities relative to each other at the instantaneous centre

62. The pitch circle of a cam is

Correct : D. The circle with centre as the centre of cam axis and radius such that it passes through the pitch point

63. The standard pressure angle is generally

Correct : D. 14

64. Frequency of oscillation of a compound pendulum having the same distance between point of suspension and the centre of gravity of mass as a simple pendulum will be

Correct : A. Less

65. Which is the false statement about a governor?

Correct : C. A sensitive governor cannot be isochronous

66. The angle of obliquity is kept small in order

Correct : D. To avoid larger throusts

67. If there are L number of links in a mechanism, then the number of possible inversions would be

Correct : D. L

68. A mechanism is an assembly of

Correct : D. four or more than four links

69. A gear box in an automobile utilises

Correct : B. Compound gear train

70. In the coupling rod mechanism of a locomotive each of the four pairs is a

Correct : D. Turning pair

71. At critical speed

Correct : C. The shaft becomes dynamically unstable with negligible lateral amplitudes

72. When sunk key is to be used the key way is

Correct : C. Provided both in shaft and hub

73. Kinetic friction is

Correct : B. Less than maximum static friction

74. Coriolis component of acceleration will exist only if

Correct : C. Two coincidental points have linear relative velocity of sliding accompanied by the rotation about fixed centres

75. In a car, transmission losses will be minimum in

Correct : B. Direct gear

76. Cam size depends upon

Correct : C. Base circle

77. In a car transmission losses will be least in which gear?

Correct : A. Direct gear

78. Klein's construction is used to determine

Correct : C. Acceleration of various parts

79. A sphere of mass 100 kg moving at 10 m/s overtakes and collides with another sphere of mass 50 kg moving at 3 m/s in the same direction. If the impact is perfectly elastic, the velocity of two masses after impact will be

Correct : A. 6.67 m/s

80. Which of the following road offers maximum resistance to automobiles?

Correct : A. Loose sand

81. The mechanism used to enlarge or reduce moments for reproducing drawings to different scales is known as

Correct : C. Pantograph

82. The frictional torque transmitted by a cone clutch is the same as that of

Correct : C. truncated conical pivot bearing

83. Froude's dynamometer is

Correct : C. Vortex type hydraulic dynamometer

84. In vibration analysis 'Beat' frequency is

Correct : B. Said to occur when two vibrations of almost equal frequency are present

85. In case of Scotch Yoke Mechanism the Coriolis component is

Correct : B. Not involved

86. A 0.5 kg weight attached to a light spring elongates it 0.981 mm. The natural frequency of the system would be approximately

Correct : D. 16 cps

87. A vibrating system is said to be stable if

Correct : A. The amplitude of vibration decreases with time

88. The cam angle is

Correct : A. The angle of rotation of the cam for a definite displacement of the follower

89. The coefficient of friction between pulley and belt is reduced to half. If the initial ratio of tension in belt is 5, then the new value will be

Correct : E. None of the above

90. In a system if the speed reduction of 60 : 1 is desired the convenient way is to use

Correct : B. Worm and worm wheel

91. Which of following gear system have minimum axial thrust?

Correct : E. Miter gears

92. In Iocomotives, swaying couple is caused due to

Correct : D. Unbalanced parts of the primary forces acting at a distance between the line of stroke of the cylinders

93. A governor is said to be isochronous when

Correct : D. There is only one equibilbrium speed which is constant for all radii of rotation of the bells within the working range

94. In a Hartnell governor if the stiffness of spring is increased the governor will

Correct : B. Become less sensitive

95. In taper roller bearing the contact angle is

Correct : D. Between 5? and 10?

96. Which of the following is a sliding pair?

Correct : D. Cross-head and guides

97. A body having an initial velocity of 10 m/s moves 200 mm in 5 sec when a force of 20 kgf is applied to it. If the acceleration due to gravity is 9 m/s2 the weight of the body should be

Correct : A. 15 kg

98. Which of the following is not a common section of V-belts

Correct : B. F

99. The speed of gas turbine is usually

Correct : C. Well above the natural frequency of vibrations

100. The direction of Corioli's component of acceleration is

Correct : A. The direction of relative velocity vector for the two coincidental points rotated by 90? in the direction of the angular velocity of the rotation of the link