5. According to uniform wear theory____. Where ,w=Angular velocity of shaft, r=radius of shaft, W=Axial lead on shaft
Correct : B. p.r=constant
6. In case of foot step bearing, the frictional force under the conditions of uniform pressure may be assumed to be acting at____.
Correct : D. (2/3)r
7. In case of foot step bearing, the frictional force under the conditions of uniform wear may be assumed to be acting at____.
Correct : B. (1/2).r
8. The ratio of friction torque for uniform pressure to uniform wear for the same dimensions and load is _______.
Correct : A. >1
9. Torque required to overcome the friction between shaft and bearing surface in case of multiple flat collar bearing is ___________.
Correct : A. independent on of collars
10. In case of flat pivot bearing,the rubbing velocity is _________.
Correct : B. zero at the center and maximum at the outer radius
11. The rate of wearing in case of flat pivot bearing is ______.
Correct : D. both (b) and (c )
12. For calculating the friction power for bearing, the assumptions made in practice are_____.
Correct : D. (a) and (c ) only
13. In case of flat pivot bearing the frictional torque transmitted for uniform pressure as compared to the frictional torque transmitted for uniform wear_____.
Correct : A. is more
14. The ratio of friction torque transmitted for uniform pressure to frictional torque transmitted for uniform wear in case of flat pivot, is equal to_______.
Correct : D. (4/3)
15. When the axial load carried by the shaft in case of flat collar bearing, is large; a number of collars are provided on the shaft. This is done____.
Correct : C. to reduce the intensity of pressure
16. Choose the correct statement regarding the safe design of a bearing.
Correct : C. when horse power lost in friction is to be determined, uniform pressure is assumed and when horse power transmitted is to be determined, uniform wear is assumed
17. For uniform pressure the ratio of frictional torque for a flat collar bearing to the frictional torque for conical collar bearing is equal to____. Where ϴ=semi-angle of the cone
Correct : C. sinϴ
18. For uniform wear, the ratio of frictional torque for a flat collar bearing to the frictional torque for conical collar bearing is equal to____. Where ϴ=semi-angle of the cone
Correct : C. sinϴ
19. The ratio of frictional torque for a conical collar bearing to that for flat collar bearing is proportional to____. Where ϴ=semi-angle of the cone
Correct : D. 1/sinϴ
20. For flat and conical pivots, the ratio of friction torque with uniform wear to friction torque with uniform pressure is ____.
Correct : D. (3/4)
21. The ratio of frictional torque produced for uniform wear to frictional torque produced for uniform pressure is ____.
Correct : A. (3/4)
22. The frictional torque for the same diameter in a conical bearing is ____.
Correct : A. more
23. The frictional torque transmitted by a conical bearing is ____.
Correct : C. more than that of flat collar bearing
24. The frictional torque produced due to friction for same shaft diameter, in conical bearing is____.
Correct : C. more than that for flat collar bearing
25. Choose the wrong statement
Correct : D. the frictional force for uniform pressure, in case of a flat collar pivot bearing, can be assumed to be acting at a distance of half of the sum of internal and external radii of the shaft
26. The ratio of frictional torque produced for uniform wear to that for uniform pressure is ____.
Correct : D. (3/4)
27. In case of pivot bearing the rate of wear is _____.
Correct : B. zero at the center of contact
28. The number of collars are provided to carry a fixed axial force in a flat collar bearing _______.
Correct : C. to decrease intensity of pressure
29. In flat pivot bearing the total moment of friction force______.
Correct : B. for uniform wear is less than that for uniform pressure
30. To be safe side in the design, the unform pressure and uniform wear is assumed respectively_____.
Correct : B. for power lost due to friction and power transmitted by friction
31. Choose the correct statement for safe design.
Correct : B. for power lost in friction uniform pressure is assumed
32. Choose the correct statement for safe design.
Correct : A. for power transmitted by friction uniform wear is assumed
33. The purpose of providing multiple collars on a flat collar pivot bearing is to ____.
Correct : C. distribute the axial load because of limiting bearing pressure on bearing
34. In a multi-collared thrust bearing consisting of 'n' collars and subjected to axial load W, load sheared by each collar is _______.
Correct : B. w/n
35. A flat foot step bearing 20 cm in diameter supports a load of 2500 kgf. The shaft is running at 420 rpm and the co-efficient is 0.09. The frictional torque, for uniform pressure, will be equal to ___.
Correct : B. 15 n-m
36. A flat foot step bearing 20 cm in diameter supports a load of 2500 kgf. The shaft is running at 420 rpm and the co-efficient is 0.09. The frictional torque, for uniform wear, will be equal to ___.
Correct : A. 11.25 n-m
37. A flat foot step bearing 20 cm in diameter supports a load of 2500 kgf. The shaft is running at 420 rpm and the co-efficient is 0.09. The power lost in overcoming friction at the bearing, will be equal to ___.
Correct : C. 659.7 watt
38. flat foot step bearing 20 cm in diameter supports a load of 2500 kgf. The shaft is running at 420 rpm and the co-efficient is 0.09. The power transmitted by the friction between the surface, will be equal to ___.
Correct : A. 493.875 watt
39. A thrust bearing having collars of external and internal diameter as 40 cm and 20 cm respectively, carries an axial load of 3000 N. The co-efficient of friction is 0.09 and shaft runs at 420 rpm. The power lost in friction is to be determined. The corresponding value of friction torque would be ____.
Correct : B. 42 n-m
40. A thrust bearing having collars of external and internal diameter as 40 cm and 20 cm respectively, carries an axial load of 3000 N. The co-efficient of friction is 0.09 and shaft runs at 420 rpm. The power lost in friction would be equal to ____.
Correct : B. 1.84 kw
41. A flat footstep bearing 10 cm radius supports a load of 3 kN. The shaft runs at 600/π r.p.m. and co-efficient of friction is 0.1.The friction torque and frictional power in watts with uniform pressure are respectively.
Correct : B. 20 n-m and 400 watts
42. A flat footstep bearing 10 cm radius supports a load of 3 kN. The shaft runs at 600/π r.p.m. and co-efficient of friction is 0.1. The friction torque and frictional power in watts with uniform wear are respectively.
Correct : B. 15 n-m and 300 watts
43. A flat foot step bearing 225 mm in diameter supports a load of 7500 N. If the co-efficient of friction is 0.09 and the shaft rotates at 60 rpm, calculate the power lost in frictional torque and frictional power in watts with uniform pressure is ___.
Correct : A. 50.62 n-m and 317.92 watt
44. Following are the details pertaining to thrust bearing 1) External and internal dia of contacting surfaces-320 mm and 200 mm resp. 2) Axial load-80 kN 3)Pr. Intensity-350 kN/m2 4) shaft speed-400 rpm 5)coefficient of friction-0.06 Calculate power lost in overcoming friction. the frictional torque and power lost in frictional
Correct : C. 635.08 nm and 26.60 kw
45. A conical pivot supports a load of 20 kN, and its semicone angle is 41.81 degree. The friction coefficient is 0.06 and shaft runs at 200 rpm. The torque required to overcome friction and power lost in friction is
Correct : D. 135.36 nm and 2.83 kw
46. The clutch is a device used______
Correct : C. to transmit power from on shaft to another
47. Advantages of positive clutch is_____
Correct : D. due to no slip between contact surfaces no heat is generated
48. Disadvantages of positive clutch is______
Correct : C. shock and noise is there during engagement
49. Torque transmitted by friction clutch_______
Correct : A. is more on the assumption of uniform pressure as compared to uniform wear
50. For multiple plate clutch having 'n' is the effective number of surfaces for transmitting power then no. of plates are
Correct : A. n+1
51. Frictional torque transmission through plate clutch is equivalent to____
Correct : D. flat roller bearing
52. In case of cone clutch, power transmission is same as that of________
Correct : C. trapezoidal pivot bearing
53. Multiple clutch is kind of_________
Correct : D. disc clutch
54. Among which clutch heat dissipation is a serious problem?
Correct : A. multiple clutch
55. In case of clutch , uniform pressure theory is applicable for
Correct : B. new clutch
56. Centrifugal clutch are used in _____
Correct : D. mopeds
57. A friction clutch should be designed on the assumption of
Correct : A. uniform wear
58. Considering the safe design, the friction clutch should be designed _______
Correct : B. assuming uniform wear
59. The equivalent coefficient of friction for a cone clutch is ____.
Correct : C. µ/sinα
60. Frictional torque transmission through multi plate clutch is equivalent to____.
Correct : D. flat roller bearing
61. In case of multiplate clutch, power transmission is same as that of ______.
Correct : B. flat pivot bearing
62. Single plate clutch is a kind of _________.
Correct : D. disc clutch
63. Which of the following is an example of friction clutch?
Correct : D. all of the above
64. The frictional torque transmitted by a disc clutch is same as that of _____.
Correct : B. flat collar bearing
65. The frictional torque transmitted by a cone clutch is same as that of ____.
Correct : D. trapezoidal pivot bearing
66. For safe design, a frictional clutch is designed assuming ____.
Correct : B. uniform wear theory
67. In multiple friction clutch, the number of active friction surfaces is ____.
Correct : D. n-1
68. Friction torque transmitted by a disc or plat clutch is same as that of ____.
Correct : B. flat collar bearing
69. For multiple plate friction clutch with n plates, the number of active surfaces n
Correct : A. n
70. A single plate clutch is transmitting power, the inner and other radii of the plate are 10 cm and 22.5 cm respectively. Using the radius uniform wear theory, the maximum pressure intensity occurs at a radius of ____.
Correct : A. 10 cm
71. Torque transmitted by single plate clutch with axial spring load = 1 kN, and inner and outer radii of 10 cm and 15 cm and µ = 0.5 with assumption of uniform wear is ____.
Correct : C. 62.5 n-m
72. A multiple clutch with 5 plate transmits torque of 400 N-m. If µ = 0.5 and inner radius = 10 cm and outer radius = 15 cm and four spring expert-axial and load per spring is ___.
Correct : C. 400 n
73. Determine the axial force required to engage a cone clutch transmitting 25 kW power at 750 rpm. Average friction diameter of the cone is 400 mm, semicone angle 10 degree and coefficient of friction 0.25.
Correct : B. 318.31 nm and 1105.47 n
74. Determine the axial force required to engage a cone clutch transmitting 25 kW power at 750 rpm. Average friction diameter of the cone is 400 mm, semicone angle 60 degree and coefficient of friction 0.25.
Correct : B. 318.31 nm and 1105.47 n
75. Can simple band brake be made of self-locking type?
Correct : C. yes, but with few limitations
76. Material used for brake lining should not have ___.
Correct : B. low heat resistance
77. pivoted block brake is a kind of ____.
Correct : B. shoe brake
78. Which type of brakes are used in electric crane?
Correct : D. double bloke brake
79. In a band brake 'a' is perpendicular distance between slack side and pivot point and 'b' is perpendicular distances between tight side and pivot point. If applied force is downwards then ___.
Correct : A. a > b
80. Brakes used in Railway engine are____.
Correct : C. shoe brake
81. The brake commonly used in motor cars ____.
Correct : D. internal expanding brake
82. When will the distance travelled by 4-wheel be less after braking?
Correct : C. when brakes applied to all 4-wheels
83. Brakes are self energizing when____.
Correct : B. frictional torque opposes the applied torque
84. In a differential band brake, as shown in fig.1the length OA is greater than OB. In order to apply the brake, the force at C should____.
Correct : C. act in downward direction
85. For the brake to be self locking, the force P at C as shown in fig.1 should____.
Correct : A. be zero
86. When brakes are applied to all the four wheels of a moving car before it is brought to rest, will be____.
Correct : B. minimum
87. Which of the following brakes is commonly used in two wheelers?
95. For ccw direction of drum rotation in fig.2 brake applied if ____.
Correct : A. a>b and p acts downwards
96. The band brake in fig.2 will be self-energizing when____.
Correct : D. drum rotates ccw and p acts downwards
97. Self-locking is not possible in the case of____.
Correct : A. simple band brake
98. A short shoe brake has angle of contact less than____degree.
Correct : C. 45
99. In block brake, the normal reaction and frictional force act at the mid-point of the block. This is true only if the angle of contact is ____
Correct : A. less than 45 degree
100. In a block brake, when the fulcrum point is below the line of action of friction point, the ratio of effort required for clockwise and counter clockwise rotation is____.