Theory of Machines | Set 1

1. The advantages of involute profile over cycloidal are given below. Identify if there is any incorrect statement

A. In the involute system, the pressure angle is constant, from commencement to end of engagement

B. The vriation in the centre distance with in limits does not affect the two mating gears in the involute system

C. The straight teeth of the basic rank for the involute profile admits of simple tools

D. The interference is inherently absent in this system

E. The profile for the flank and face is a single curve in the involute system

Correct : D. The interference is inherently absent in this system

2. A reverted gear train is one is which

A. The direction of rotation of first and last gear is the same

B. The firection of rotation of first and the last gear is opposite

C. The first and last gear are on the same shaft

D. The first and last gear are essentially on separate but parallel shafts

E. None of the above

Correct : C. The first and last gear are on the same shaft

3. Slip in turning belt is

4. The effect of creep in case of cross-belt drive is

A. To increase the power transmitted

B. To increase the speed of driven pulley

C. (A) and (B) above together

D. To reduce the speed of the driven pulley and consequently reduce the power output

E. None of the above

Correct : D. To reduce the speed of the driven pulley and consequently reduce the power output

5. A cylindrical type cam is one

A. With circular type motion of follower

B. With cylindrical shape of follower

C. With disc type cam in which the position of the follower is determined by the radial distance from the cam axis.

D. With cricumferential contour cut in the surface of the cylinder which rotates about its axis

E. With cylindrical roller follower

Correct : D. With cricumferential contour cut in the surface of the cylinder which rotates about its axis

7. In case of cross-helical worm the axes of two shafts are

8. Ackermann steering gear consists of

9. Identify the incorrect statement if any

A. In case of free vibrations the external force is applied at the ends only

B. Damping is resistance to the oscillartion

C. When the frequency of the external exciting force coincides with the natural frequency of the system, state of resonance is reached

D. Forced vibrations are independent of natural frequency of vibration

E. None of the above

Correct : A. In case of free vibrations the external force is applied at the ends only

10. V-belts with E type cross-section are generally used in

11. In a cam and follower mechanism, for the uniform velocity of the followers the displacement curve will have

A. No slope

B. Constant slope

C. Slope in positive direction only

D. Slope in both positive and negative direction

E. None of the above

Correct : B. Constant slope

13. Coriolis component is encountered in

A. Slider crank mechanism

B. Four bar chain mechanism

C. Quich return mechanism

D. (A) and (B) above

E. (A) and (C) above

Correct : C. Quich return mechanism

14. The mass moment of inertia is

A. The resistance to angular acceleration

B. The mass of every element of a body multiplied by its distance from the axis

C. Any of the above

D. None of the above

E. Cross-head

Correct : A. The resistance to angular acceleration

16. Which of the following gears is free from axial thrust

17. In case of hypoid gears the mutual position of shafts will be

18. Coriorli's component of acceleration exists whenever a point moves along a path that has

A. Gravitational acceleration

B. Rotational motion

C. Linear displacement

D. Tangential acceleration

E. Centripetal acceleration

Correct : B. Rotational motion

19. The spring constant k of a coil-spring is

A. inversely proportional to the square of the number of coils in the spring

B. Sperm

C. directly proportional to the number of coils in the spring

D. inversely proportional to the number of coils in the spring

E. directly proportional to the square of the number of coils in the spring

Correct : E. directly proportional to the square of the number of coils in the spring

20. In case of spur gears the profile is

A. Radius that connects the root circle to the profile of the tooth

B. The curve forming face and flank

C. The part of the tooth surface lying below the pitch surface

D. The surface of the top of tooth

E. The width of the gear tooth measured axially along the pitch surface

Correct : B. The curve forming face and flank

21. Dynamic of machines deals with

A. The relative motion between the parts, neglecting the consideration of forces

B. The forces acting on the parts of the machine

C. The apparatus for applying mechanical power

D. The number of inter-related parts, each having a definite motion

E. None of the above

Correct : B. The forces acting on the parts of the machine

22. Klein's construction can be used when

A. Crank has a uniform angular velocity

B. Crank has a uniform angular acceleration

C. Crank has a non-uniform angular velocity

D. (A) and (B) above

E. (A) and (C) above

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

23. In the elliptical trammel mechanism, the mid-point of the link connecting the two sliders traverses

24. A dadial follower is

A. One that reciprocates in the guides

B. One that oscillates

C. One in which the follower translates along an axis passing through the cam centre of rotation

D. One in which the axis of the following movement is displaced from the cam centre

E. None of the above

Correct : C. One in which the follower translates along an axis passing through the cam centre of rotation

26. A shaft having one end fixed has a disc oscillating freely at the other end. If the shaft stiffness, increases the natural frequency of vibrations will

27. If a machine uses four V belts, while purchasing care should be taken to ensure that

A. All belts are same section

B. All above

C. All belts are of same batch number

D. All belts are of same size

E. All belts are of same manufacturers

Correct : B. All above

28. In case of balancing problems pertaining to locomotives, the resultant unbalanced force is minimum when

A. Half of the reciprocating masses are balanced by rotating masses

B. 1/2 of the reciprocating mass are balanced by equivalent rotating mass

C. More than half of the reciprocating masses are balanced by rotating masses

D. Reciprocating masses are balanced half by equivalent opposite reciprocating masses and the balance by rotating masses

E. None of the above

Correct : A. Half of the reciprocating masses are balanced by rotating masses

29. Which of the following is a higher pair?

A. A shaft revolving in a bearing

B. Piston reciprocating inside the cylinder

C. Automobile steering gear

D. Ball and socket

E. None of the above

Correct : E. None of the above

30. The vibrations in which the restoring forces are not proportional to the displacements and the first power of velocity are known as

A. Bearing vibrations

B. Over damped vibrations

C. Torsional vibrations

D. Non-linear vibrations

E. Under damped vibrations

Correct : A. Bearing vibrations

31. If a particle of a link has a velocity when changes both in magnitude and direction at any instant, then

A. It must have three components of acceleration e.g. centripetal, centrifugal and gravitational

B. It must have two components of acceleration e.g. centripetal, and tangential

C. It must have three components of acceleration e.g. centripetal centrifugal and tangential

D. It must have four components of acceleration e.g. centripetal, centrifugal gravitational and tangential

E. It must have only unidirectional acceleration

Correct : B. It must have two components of acceleration e.g. centripetal, and tangential

33. In case of involute gears

A. Interference is inherently absent

B. A convex flank is always in contact with concave flank

C. Variation in centre distance of shafts increases radial force

D. Pressure angle is constant throughout the teeth engagement

E. None of the above

Correct : D. Pressure angle is constant throughout the teeth engagement

34. The rotor of a ship rotates in anticlock wise direction when viewed from the bow end and the ship takes a left turn. The effect of gyroscopic couple on the ship is

A. to lower the bow and raise the stern

B. to raise the bow and lower then stern

C. to roll the ship slightly clockwise when viewed fro bow end

D. None of the above

E. None of the above

Correct : B. to raise the bow and lower then stern

35. In case of gears, the module is

A. The length of the pitch circule diameter per tooth

B. The number of teeth per unit length on pitch circle diameter

C. The pistance measured along the pitch circle from a point on one tooth to a corresponding point on the adjacent point

D. Any of the above

E. None of the above

Correct : A. The length of the pitch circule diameter per tooth

36. Hammer blow in locomotives results in

A. Variable horizontal force

B. Tendency to lift wheel from rails

C. Uniform torque

D. Pulsating torque

E. Uneven speed

Correct : B. Tendency to lift wheel from rails

37. In Iocomotive operation, the swaying couple results due to

38. Which of the following is a centrifugal type governor?

39. The maximum efficiency of a screw jack provided with square threads and angle of friction 30? will be

40. A governor is said to be stable when

A. There is one radius of the governor weights for each equilibrium speed

B. There is minimum change of the radius of the governor weights at a operating speed

C. The position of balls does not change within the operating speed

D. The position of balls changes within permissible limits within the working range of a governor

E. None of the above

Correct : A. There is one radius of the governor weights for each equilibrium speed

41. Klien's construction gives graphical construction for

42. Can simple band brake be made self-energising type

43. For speed reduction in the ratio of 100 the type of gear preferred is

44. The moment of friction with the assumption of uniform wear to uniform pressure is

45. The type of governor used in record players for adjusting the speed of turn table generally is

46. A belt drive is

A. A positive drive

B. Not a positive drive

C. Meant for small torque transmission only

D. Used only when the two pulleys have parallel axis

E. None of the above

Correct : B. Not a positive drive

47. The engine of an aeroplane rotates in a clockwise direction when seen from the tail end and the aeroplane takes a turn torwards left. The effect of gyroscopic couple on aeroplane is

A. to raise the nose and dip the tail

B. to dip the nose and raise the tail

C. to roll the aeroplane slightly in the clockwise direction when viewed from tail end

D. None of the above

E. None of the above

Correct : A. to raise the nose and dip the tail

48. A V belt designated as C 3048/120 will have

A. Approximately 120 inch inside length

B. Approximately 120 cm inside length

C. C section, length unspecified

D. Width 120 mm

E. None of the above

Correct : A. Approximately 120 inch inside length

49. A cycle chain is a kinematic chain

50. A kinematic chain must have at least

A. Four links and two turning pairs

B. Four links and four turning pairs

C. Four links and five turning pairs

D. Two links and two turning pairs

E. Three links and two turning pairs

Correct : B. Four links and four turning pairs

51. In order to balance the reciprocating masses, the conditions to be satisfied are

A. Primary forces must balance

B. All above conditions must be satisfied

C. Secondary couples must balance

D. Primary couples must balance

E. Secondary forces must balance

Correct : B. All above conditions must be satisfied

52. A cam profile is the

A. Actual working contour of the cam

B. Profile of path traced by a cam follower

C. Total surface area of the cam

D. Path which the cam follower traces

E. The profile of the path to be traced by the mechanism driven by follower

Correct : A. Actual working contour of the cam

54. Which dynamometer will be most suitable for measuring the BHP of an automobile engine?

55. In case of locomotives, the effect of hammer blow is counteracted by

A. Flanges of the tyres of the wheels

B. Balancing weights

C. Inside section of the rails

D. Dead weight of the engine

E. All of the above

Correct : D. Dead weight of the engine

56. A 0.5 kg weight attached to a light spring elogates it 7.87 mm. The natural frequency of the system would be in the range

57. The secondary critical speed of a shaft occurs at

A. Twice the primary critical speed

B. Occurs only when there are more than 2 rotors on a shaft

C. Four times the primary critical speed

D. If the externam exciting system has a frequency other than the primary critical speed

E. Half the primary critical speed

Correct : A. Twice the primary critical speed

58. Which of the following instruments may be used in vibration measurements?

59. In locomotives the unbalanced part of the primary disturbing force due to reciprocating masses, cause

A. Variation of tractive effect

B. Periodical vibrations

C. Lifting of locomotive

D. Oscillation in vertical planes

E. Hammer blow

Correct : A. Variation of tractive effect

60. The 'crowning' of flat pulleys is generally done pulley

A. To reduce belt friction

B. To prevent belt joining from damaging the belt surface

C. To prevent the belt from running off the pulley

D. In case of cross belt drives only

E. None of the above

Correct : C. To prevent the belt from running off the pulley

61. V belt having cross-section A is suitable for usual load of 5 HP. If 15 HP load is to be transmitted

A. Toothed belts may be used

B. 3 Vee belts using 3 groove pulley may be used

C. Machine arrangement may be modified

D. Drive system may be changed

E. Gear system may be adopted

Correct : B. 3 Vee belts using 3 groove pulley may be used

62. The efficiency in case of worm gear drives is generally in the range

63. Two shafts have their axes not in the same straight line. Also their axes are not parallel but intersecting. Which of the following coupling can be used for these shafts?

64. Coriolis component is not involved in

A. Andreau variable stroke engine mechanism

B. Slider crank mechanism

C. Line sliding in a swivelling pin

D. Quick return mechanism

E. Tangent cam acceleration

Correct : B. Slider crank mechanism

65. Idler pulley is used for

A. Maintaining belt tension

B. Changing direction of rotation

C. For stopping motion frequently

D. For running during idling periods only

E. None of the above

Correct : A. Maintaining belt tension

68. By using large thread angles in a lifting machine

A. The mechanical advantage will be low

B. The mechanical advantage will be high

C. The load will be sustained in absence of effort

D. The load will be easily lifted

E. While unloading, little effort will be required

Correct : A. The mechanical advantage will be low

69. The throw of a cam is the maximum distance of the follower from

71. Which of the following is a lower pair?

72. Which of the following is a dead weight governor?

73. The mechanism used in a petrol engine is

A. Crank mechanism

B. Slider mechanism

C. Slider crank mechanism

D. Natural line and circular mechanism

E. None of the above

Correct : C. Slider crank mechanism

74. In the Crossby engine indicator which one of the following mechanism is used?

A. Slider-crank mechanism

B. Scotch yoke mechanism

C. Scotch yoke mechanism

D. Modified pantograph mechanism

E. None of the above

Correct : C. Scotch yoke mechanism

75. Timing belt

A. Have no slip

B. Have maximum slip during starting

C. Slip in proportion to the time of operation

D. Are used to determine the life time of a belt

E. None of the above

Correct : A. Have no slip

77. For a rational number for the pitch circle diameter and a rational number of teeth on the wheel, the circular pitch will work out to

78. A swinging field type dynamometer is

A. Torsion dynamometer

B. Vortex type dynamometer

C. Friction dynamometer

D. Electrical dynamometer

E. Transmission type of dynamometer

Correct : D. Electrical dynamometer

79. Forced vibrations

A. Are followed by free vibrations

B. Are preceded by free vibrations

C. Take place at a frequency more than natural frequency

D. Are independent of natural frequency

E. None of the above

Correct : D. Are independent of natural frequency

80. 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 inelastic the velocity of of two masses after impact will be

81. The critical speed of a shaft is affected by

82. A standard gear cutter No. 3 is marked to cut 35-54 teeth. It implies that

A. The cutter is to be replaced after cutting 54 teeth

B. The cutter will be suitable for gears having 35 to 54 teeth

C. The cutter will be suitable for spur gear teeth cutting only

D. The cutter will provide correct profile for any gear having number of teeth in the range 35 to 54

E. None of the above

Correct : B. The cutter will be suitable for gears having 35 to 54 teeth

83. A kinematic chain requires minimum of

A. 3 links and 3 turning pairs

B. 4 links and 4 turning pairs

C. 3 links and 4 turning pairs

D. 2 links and 3 turning pairs

E. 4 links and 5 turning pairs

Correct : B. 4 links and 4 turning pairs

85. An axial flow fan balanced at one speed often exhibits substantial vibrational effects when operated at other speeds, mainly due to

A. Unbalanced parts of fan

B. Aerodynamic unbalance

C. Primary critical speed effect

D. Secondary critical speed effect

E. Vibration in air

Correct : B. Aerodynamic unbalance

87. Which of the following is a spring controlled governor?

88. The sum of the tensions when the belt is running on the pulley is

A. Less than the initial tension

B. More than the initial tension

C. More than twise the initial tension

D. Half the initial tension

E. None of the above

Correct : C. More than twise the initial tension

89. Klien's construction gives a graphical construction for

A. Velocity polygon

B. Slider crank mechanism

C. Angular accelerations

D. Acceleration polygon

E. Four bar chain mechanism

Correct : D. Acceleration polygon

90. In order that a belt may not run off the pulley

A. It should be properly tightened

B. The centre line of the belt as it approaches the pulley must lie in a plane perpendicular to the axis of that pulley

C. The belt should be provided with frictional material

D. The belt should be provided with a guide

E. None of the above

Correct : B. The centre line of the belt as it approaches the pulley must lie in a plane perpendicular to the axis of that pulley

91. The gears are considered to be operating in medium velocity range if their peripheral velocity lies in the range

92. Motor cycle shock sbsorbers are generally designed for

93. A point on a link connecting double slider crank chain, traces a

94. Velocity of sliding between two mating gear surfaces can be defined as

A. Sum of their angular velocities x distance between pitch point and point of contact.

B. Sum of their angular velocities x distance between their centres of rotation.

C. Sum of their angular velocities x difference between their pitch circle diameters

D. None of these

E. None of the above

Correct : A. Sum of their angular velocities x distance between pitch point and point of contact.

95. Identify incorrect statement regarding the flywheel, if any

A. It is provided to minimise vibration of engine

B. It takes care of output fluctuations and controls input accordingly

C. It is provided to control engine speed

D. All above

E. In help in starting engine

Correct : D. All above

97. In case of gears, the interference takes place

A. Whenever the forms of the mating teeth are such that contact between them can occur at some place other than along the correct path of contact

B. When gears do not move smoothly in absence of lubrication

C. When the pitch of the gears is not same

D. When the gear teeth are under cut

E. None of the above

Correct : A. Whenever the forms of the mating teeth are such that contact between them can occur at some place other than along the correct path of contact

98. In case of solid friction, when tan ? =

A. The body A will move over the surface B irrespective of the magnitude of the force F applied on the body

B. tan ? can be equal to

C. tan ? can never be equal to

D. No motion of body A on surface B is possible, irrespective of how large the magnitude of force F applied on the body may be

E. tan ? can be equal to

Correct : A. The body A will move over the surface B irrespective of the magnitude of the force F applied on the body

99. Which of the following is a dead weight type governor?

100. Which of the following is not a positive drive?

Quiznetik

Theory of Machines | Set 1

1. The advantages of involute profile over cycloidal are given below. Identify if there is any incorrect statement

2. A reverted gear train is one is which

3. Slip in turning belt is

4. The effect of creep in case of cross-belt drive is

5. A cylindrical type cam is one

6. A pulley in a belt-drive acts as a

7. In case of cross-helical worm the axes of two shafts are

8. Ackermann steering gear consists of

9. Identify the incorrect statement if any

10. V-belts with E type cross-section are generally used in

11. In a cam and follower mechanism, for the uniform velocity of the followers the displacement curve will have

12. Pitch of gears is expressed by

13. Coriolis component is encountered in

14. The mass moment of inertia is

15. The number of forks provided in a Hooke's joint is

16. Which of the following gears is free from axial thrust

17. In case of hypoid gears the mutual position of shafts will be

18. Coriorli's component of acceleration exists whenever a point moves along a path that has

19. The spring constant k of a coil-spring is

20. In case of spur gears the profile is

21. Dynamic of machines deals with

22. Klein's construction can be used when

23. In the elliptical trammel mechanism, the mid-point of the link connecting the two sliders traverses

24. A dadial follower is

25. The pulley in a belt drive acts as

26. A shaft having one end fixed has a disc oscillating freely at the other end. If the shaft stiffness, increases the natural frequency of vibrations will

27. If a machine uses four V belts, while purchasing care should be taken to ensure that

28. In case of balancing problems pertaining to locomotives, the resultant unbalanced force is minimum when

29. Which of the following is a higher pair?

30. The vibrations in which the restoring forces are not proportional to the displacements and the first power of velocity are known as

31. If a particle of a link has a velocity when changes both in magnitude and direction at any instant, then

32. Which of the following oil has highest specific gravity?

33. In case of involute gears

34. The rotor of a ship rotates in anticlock wise direction when viewed from the bow end and the ship takes a left turn. The effect of gyroscopic couple on the ship is

35. In case of gears, the module is

36. Hammer blow in locomotives results in

37. In Iocomotive operation, the swaying couple results due to

38. Which of the following is a centrifugal type governor?

39. The maximum efficiency of a screw jack provided with square threads and angle of friction 30? will be

40. A governor is said to be stable when

41. Klien's construction gives graphical construction for

42. Can simple band brake be made self-energising type

43. For speed reduction in the ratio of 100 the type of gear preferred is

44. The moment of friction with the assumption of uniform wear to uniform pressure is

45. The type of governor used in record players for adjusting the speed of turn table generally is

46. A belt drive is

47. The engine of an aeroplane rotates in a clockwise direction when seen from the tail end and the aeroplane takes a turn torwards left. The effect of gyroscopic couple on aeroplane is

48. A V belt designated as C 3048/120 will have

49. A cycle chain is a kinematic chain

50. A kinematic chain must have at least

51. In order to balance the reciprocating masses, the conditions to be satisfied are

52. A cam profile is the

53. The number of instantaneous centres for a four bar chain mechanism would be

54. Which dynamometer will be most suitable for measuring the BHP of an automobile engine?

55. In case of locomotives, the effect of hammer blow is counteracted by

56. A 0.5 kg weight attached to a light spring elogates it 7.87 mm. The natural frequency of the system would be in the range

57. The secondary critical speed of a shaft occurs at

58. Which of the following instruments may be used in vibration measurements?

59. In locomotives the unbalanced part of the primary disturbing force due to reciprocating masses, cause

60. The 'crowning' of flat pulleys is generally done pulley

61. V belt having cross-section A is suitable for usual load of 5 HP. If 15 HP load is to be transmitted

62. The efficiency in case of worm gear drives is generally in the range

63. Two shafts have their axes not in the same straight line. Also their axes are not parallel but intersecting. Which of the following coupling can be used for these shafts?

64. Coriolis component is not involved in

65. Idler pulley is used for

66. Contact ratio of gear should be

67. The number of nodes in a shaft carrying three rotors will be

68. By using large thread angles in a lifting machine

69. The throw of a cam is the maximum distance of the follower from

70. The number of degrees of feeedom for a vibrating beam will be

71. Which of the following is a lower pair?

72. Which of the following is a dead weight governor?

73. The mechanism used in a petrol engine is

74. In the Crossby engine indicator which one of the following mechanism is used?

75. Timing belt

76. The speed ratio in case of micro gears is

77. For a rational number for the pitch circle diameter and a rational number of teeth on the wheel, the circular pitch will work out to

78. A swinging field type dynamometer is