MCQOPTIONS
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MCQOPTIONS
This section includes 104 Mcqs, each offering curated multiple-choice questions to sharpen your Machine Design knowledge and support exam preparation. Choose a topic below to get started.
| 51. |
A bar is subjected to a combination of a steady load of 60 kN and a load fluctuating between - 10 kN and 90 kN. The corrected endurance limit of the bar is 150 MPa. the yield strength of the material is 480 MPa and the ultimate strength of the material is 600 MPa. The bar cross-section is square with side a. If the factor of safety is 2, the value of a (in mm), according to the modified Goodman's criterion, is _________ (correct to two decimal places). |
| A. | 31.62 |
| B. | 31.6 |
| C. | 31.52 |
| D. | 31 |
| Answer» B. 31.6 | |
| 52. |
A spur pinion of pitch diameter 50 mm rotates at 200 rad/s and transmits 3 kW power. The pressure angle of the tooth of the pinion is 20 . Assuming that only one pair of the teeth is in contact, the total force (in Newton) exerted by a tooth of the pinion on the tooth on a mating gear is ________. |
| A. | 638.5 N. |
| B. | 637.5 N. |
| C. | 636.5 N. |
| D. | 639.5 N. |
| Answer» B. 637.5 N. | |
| 53. |
Two mating spur gears have 40 and 120 teeth respectively. The pinion rotates at 1200 rpm and transmits a torque of 20 N.m. The torque transmitted by gear is |
| A. | 6.6 Nm |
| B. | 20 Nm |
| C. | 40 Nm |
| D. | 60 Nm |
| Answer» E. | |
| 54. |
A wire rope is designated as 6 x 19 standard hoisting. The numbers 6 19 represent |
| A. | diameter in millimeter length in meter |
| B. | diameter in centimeter length in meter |
| C. | number of strands number of wires in each strand |
| D. | number of wires in each Strand number of strands |
| Answer» D. number of wires in each Strand number of strands | |
| 55. |
A single-plate clutch has a friction disc with inner and outer radii of 20 mm and 40 mm, respectively. The friction lining in the disc is made in such a way that the coefficient of friction varies radially as = 0.01 r, where r is in mm. The clutch needs to transmit a friction torque of 18.85 kN mm. As per uniform pressure theory, the pressure (in MPa) on the disc is __________. |
| A. | 0.5 MPa |
| B. | 0.4 MPa |
| C. | 0.6 MPa |
| D. | 1.5 MPa |
| Answer» B. 0.4 MPa | |
| 56. |
A shaft is subjected to pure torsional moment. The maximum shear stress developed in the shaft is 100 MPa. The yield and ultimate strengths of the shaft material in tension are 300 MPa and 450 MPa, respectively. The factor of safety using maximum distortion energy (Von-Mises) theory is _______ . |
| A. | 1.732 |
| B. | 2.732 |
| C. | 0.732 |
| D. | 1.622 |
| Answer» B. 2.732 | |
| 57. |
Fatigue life of a material for a fully reversed loading condition is estimated from |
| A. | 195.61 N |
| B. | 194.61 N |
| C. | 193.61 N |
| D. | 192.61 N |
| Answer» B. 194.61 N | |
| 58. |
At a critical point in a component, the state of stress is given as |
| A. | 1.8 |
| B. | 1.4 |
| C. | 2.8 |
| D. | 2.4 |
| Answer» B. 1.4 | |
| 59. |
The uniaxial yield stress of a material is 300 MPa. According to Von Mises criterion, the shear yield stress (in MPa) of the material is _______. |
| A. | 173.28 |
| B. | 172.28 |
| C. | 171.28 |
| D. | 169.28 |
| Answer» B. 172.28 | |
| 60. |
A self-aligning ball bearing has a basic dynamic load rating (C |
| A. | below 0.5 |
| B. | 0.5 to 0.8 |
| C. | 0.8 to 1.0 |
| D. | above 1.0 |
| Answer» B. 0.5 to 0.8 | |
| 61. |
A butt weld Joint is developed on steel plates having yield and ultimate tensile strength of 500 MPa and 700 MPa, respectively. The thickness of the plates is 8 mm and width is 20 mm. Improper selection of welding parameters caused an undercut of 3 mm depth along the weld. The maximum transverse tensile load (in kN) carrying capacity of the developed weld Joint is _________. |
| A. | 70 kN |
| B. | 71 kN |
| C. | 69 kN |
| D. | 72 kN |
| Answer» B. 71 kN | |
| 62. |
A machine element is subjected to the following bi-axial state of stress; |
| A. | 1.0 |
| B. | 2.0 |
| C. | 2.5 |
| D. | 3.3 |
| Answer» C. 2.5 | |
| 63. |
Square key of side d/4 each and length l is used to transmit torque T from the shaft of diameter d to the hub of a pulley. Assuming the length of the key to be equal to the thickness of the pulley, the average shear stress developed in the key is given by |
| A. | <table><tr><td rowspan="2"></td><td style="border-bottom:1px solid #000000;vertical-align:bottom;padding-bottom:2px;"><center>4T</center></td><td rowspan="2"></td></tr><td align="center">ld</td></table> |
| B. | <table><tr><td rowspan="2"></td><td style="border-bottom:1px solid #000000;vertical-align:bottom;padding-bottom:2px;"><center>16T</center></td><td rowspan="2"></td></tr><td align="center">ld </td></table> |
| C. | <table><tr><td rowspan="2"></td><td style="border-bottom:1px solid #000000;vertical-align:bottom;padding-bottom:2px;"><center>8T</center></td><td rowspan="2"></td></tr><td align="center">ld </td></table> |
| D. | <table><tr><td rowspan="2"></td><td style="border-bottom:1px solid #000000;vertical-align:bottom;padding-bottom:2px;"><center>16T</center></td><td rowspan="2"></td></tr><td align="center"> d<sup>3</sup></td></table> |
| Answer» D. <table><tr><td rowspan="2"></td><td style="border-bottom:1px solid #000000;vertical-align:bottom;padding-bottom:2px;"><center>16T</center></td><td rowspan="2"></td></tr><td align="center"> d<sup>3</sup></td></table> | |
| 64. |
A solid circular shaft needs to be designed to transmit a torque of 50 N.m. If the allowable shear stress of the material is 140 MPa, assuming a factor of safety of 2, minimum allowable design diameter in mm is |
| A. | 8 |
| B. | 16 |
| C. | 24 |
| D. | 34 |
| Answer» C. 24 | |
| 65. |
Which one of the following is criterion in the design of hydrodynamic Journal bearings? |
| A. | Sommerfield number |
| B. | Rating life |
| C. | Specific dynamic capacity |
| D. | Rotation factor |
| Answer» B. Rating life | |
| 66. |
If the ratio of the diameter of rivet hole to the pitch of rivets is 0.25, then the tearing efficiency of the Joint is |
| A. | 0.50 |
| B. | 0.75 |
| C. | 0.25 |
| D. | 0.87 |
| Answer» C. 0.25 | |
| 67. |
Which one of the following is the most conservation fatigue failure criterion? |
| A. | Soderberg |
| B. | Modified Goodman |
| C. | ASME Elliptic |
| D. | Gerber |
| Answer» B. Modified Goodman | |
| 68. |
A static load is mounted at the centre of a shaft rotating at uniform angular velocity. This shaft will be designed for |
| A. | the maximum compressive stress (static) |
| B. | the maximum tensile stress (static) |
| C. | the maximum bending moment (static) |
| D. | fatigue loading |
| Answer» E. | |
| 69. |
In a structure subjected to fatigue loading, the minimum and maximum stresses developed in a cycle are 200 MPa and 400 MPa respectively. The value of stress amplitude (in MPa) is _____. |
| A. | 110 |
| B. | 120 |
| C. | 100 |
| D. | 200 |
| Answer» D. 200 | |
| 70. |
A rotating steel shaft is supported at the ends. It is subjected to a point load at the center. The maximum bending stress developed is 100 MPa. If the yield, ultimate and corrected endurance strength of the shaft material are 300 MPa, 500 MPa and 200 MPa, respectively, then the factor of safety for the shaft is ______. |
| A. | 2 |
| B. | 4 |
| C. | 5 |
| D. | 6 |
| Answer» B. 4 | |
| 71. |
Given that the tooth geometry factor is 0.32 and the combined effect of dynamic load and allied factors intensifying the stress is 1.5; the minimum allowable stress (in MPa) for the gear material is |
| A. | 242.0 |
| B. | 166.5 |
| C. | 121.0 |
| D. | 74.0 |
| Answer» C. 121.0 | |
| 72. |
Interference in a pair of gears is avoided, if the addendum circles of both the gears intersect common tangent to the base circles with in the points of tangency. |
| A. | True |
| B. | False |
| C. | True,False |
| D. | None |
| Answer» B. False | |
| 73. |
For a pinion of 15 teeth, under cutting ______ (increases/decreases) with _______(increase/ decrease) of pressure angle. |
| A. | Interference decreases with increase in pressure |
| B. | Interference increase with decreases in pressure |
| C. | Interference increase with increase in pressure |
| D. | None of the above |
| Answer» B. Interference increase with decreases in pressure | |
| 74. |
A thin spherical pressure vessel of 200 mm diameter and 1 mm thickness is subjected to an internal pressure varying from 4 to 8 MPa. Assume that the yield, ultimate, and endurance strength of material are 600,800 and 400 MPa respectively. The factor of safety as per Goodman's relation is |
| A. | 2.0 |
| B. | 1.6 |
| C. | 1.4 |
| D. | 1.2 |
| Answer» C. 1.4 | |
| 75. |
Match the type of gears with their most appropriate description. |
| A. | P 2, Q 4, R 1, S 6 |
| B. | P 1, Q 4, R 5, S 6 |
| C. | P 2, Q 6, R 4, S 2 |
| D. | P 6, Q 3, R 1, S 5 |
| Answer» B. P 1, Q 4, R 5, S 6 | |
| 76. |
The maximum wheel torque that can be completely braked is |
| A. | 200 N.m |
| B. | 382 N.m |
| C. | 604 N.m |
| D. | 844 N.m |
| Answer» C. 604 N.m | |
| 77. |
The maximum tension that can be generated in the band during braking is |
| A. | 1200 N |
| B. | 2110 N |
| C. | 3224 N |
| D. | 4420 N |
| Answer» C. 3224 N | |
| 78. |
In a band brake the ratio of tight side band tension to the tension on the slack side is 3. If the angle of overlap of band on the drum is 180 , the coefficient of friction required between drum and the band is |
| A. | 0.20 |
| B. | 0.25 |
| C. | 0.30 |
| D. | 0.35 |
| Answer» E. | |
| 79. |
For the given statements : |
| A. | Both I and II are false |
| B. | I is true and II is false |
| C. | I is false and II is true |
| D. | Both I and II are true |
| Answer» E. | |
| 80. |
The yield strength of a steel shaft is twice its endurance limit. Which of the following torque fluctuations represent the most critical situation according to Soderberg criterion? |
| A. | T to + T |
| B. | T/2 to + T |
| C. | 0 to + T |
| D. | + T/2 to + T |
| Answer» B. T/2 to + T | |
| 81. |
Fatigue strength of rod subjected to cyclic axial force is less than that of a rotating beam of the same dimensions subjected to steady lateral force. [True/ False] |
| A. | True,False |
| B. | False |
| C. | True |
| D. | None |
| Answer» D. None | |
| 82. |
In a shaft with a transverse hole, as the hole to the shaft diameter ratio_____(increase/ decrease), the torsional stress concentration factor ______ (increases/ decreases) |
| A. | Increase, decreases |
| B. | Increase |
| C. | decreases |
| D. | None of these |
| Answer» B. Increase | |
| 83. |
Modern gear tooth profile is given involute shape because |
| A. | this is a very easy curve for manufacturing |
| B. | sliding does not takes place anywhere on meshing teeth |
| C. | involute is the only profile that gives conjugate action |
| D. | change in the centre distance does not change gear ratio |
| Answer» E. | |
| 84. |
For full depth of involute spur gears, minimum number of teeth of pinion to avoid interference depends upon |
| A. | pressure angle |
| B. | speed ratio |
| C. | circular pitch |
| D. | pitch diameter |
| Answer» B. speed ratio | |
| 85. |
The basic load rating of a ball bearing is |
| A. | the maximum static radial load that can be applied without causing any plastic deformation of bearing components |
| B. | the radial load at which 90% of the group of apparently identical bearings run for on million revolutions before the first evidence of failure |
| C. | the maximum radial load that can be applied during operation without any plastic deformation of bearing components |
| D. | a combination of radial and axial loads that can be applied without any plastic deformation |
| Answer» C. the maximum radial load that can be applied during operation without any plastic deformation of bearing components | |
| 86. |
The dynamic load capacity of 6306 bearing is 22 kN. The maximum radial load it can sustain to operate at 600 rev/min, for 2000 hours is |
| A. | 4.16 kN |
| B. | 3.60 kN |
| C. | 6.25 kN |
| D. | 5.29 kN |
| Answer» E. | |
| 87. |
The piston rod of diameter 20 mm and length 700 mm in a hydraulic cylinder is subjected to a compressive force of 10 kN due to the internal pressure. The end conditions for the rod may be assumed as guided at the piston end and hinged at the other end. The Young's modulus is 200 GPa. The factor of safety for the piston rod is |
| A. | 0.68 |
| B. | 2.75 |
| C. | 6.32 |
| D. | 11.0 |
| Answer» D. 11.0 | |
| 88. |
To restore stable operating condition in a hydrodynamic Journal bearing, when it encounters higher magnitude of loads |
| A. | oil viscosity is to be decreased |
| B. | oil viscosity is to be increased |
| C. | oil viscosity index is to be increased |
| D. | oil viscosity index is to be decreased |
| Answer» C. oil viscosity index is to be increased | |
| 89. |
In thick film hydrodynamic Journal bearings, the coefficient of friction |
| A. | increase with increase in load |
| B. | is independent on load |
| C. | decreases with increase in load |
| D. | may increase or decrease with increase in load |
| Answer» D. may increase or decrease with increase in load | |
| 90. |
A bolt of major diameter 12 mm is required to clamp two steel plates. Cross sectional area of the threaded portion of the bolt is 84.3 mm2. The length of the threaded portion in grip is 30 mm, while the length of the unthreaded portion in grip is 8 mm. Young's modulus of material is 200 GPa. The effective stiffness (in MN/m) of the bolt in the clamped zone is _____. |
| A. | 468.9 MN/m |
| B. | 46 MN/m |
| C. | 68.9 MN/m |
| D. | 8.9 MN/m |
| Answer» B. 46 MN/m | |
| 91. |
The resultant shear stress on bolt P is closest to: |
| A. | 132 MPa |
| B. | 159 MPa |
| C. | 178 MPa |
| D. | 195 MPa |
| Answer» C. 178 MPa | |
| 92. |
Spherical roller bearings are normally used |
| A. | for increased radial load |
| B. | for increased thrust load |
| C. | when there is less radial load |
| D. | to compensate for angular misalignment |
| Answer» E. | |
| 93. |
Starting friction is low in |
| A. | hydrostatic lubrication |
| B. | hydrodynamic lubrication |
| C. | mixed (or semi fluid) lubrication |
| D. | boundary lubrication |
| Answer» B. hydrodynamic lubrication | |
| 94. |
Match the rolling element bearings with the most appropriate loading condition |
| A. | a p, b r, c s, d q |
| B. | a r, b p, c s, d t |
| C. | a q, b r, c s, d t |
| D. | a p, b r, c t, d s |
| Answer» D. a p, b r, c t, d s | |
| 95. |
If the load on a ball bearing is reduced to half, the life of the ball bearing will |
| A. | increase 8 times |
| B. | increase 4 times |
| C. | increase 2 times |
| D. | not change |
| Answer» B. increase 4 times | |
| 96. |
Bolts in the flanged end of pressure vessel are usually pre-tensioned. Indicate which of the following statements is true |
| A. | Pre-tensioning helps to seal the pressure vessel |
| B. | Pre-tensioning increase the fatigue life of the bolts |
| C. | Pre-tensioning reduces the maximum tensile stress in the bolts |
| D. | Pre-tensioning helps to reduce the effect of pressure pulsations in the pressure vessels |
| Answer» C. Pre-tensioning reduces the maximum tensile stress in the bolts | |
| 97. |
The bolts in a rigid flanged coupling connecting two shafts transmitting power are subjected to |
| A. | shear force and bending moment |
| B. | axial force |
| C. | torsion |
| D. | torsion and bending moment |
| Answer» B. axial force | |
| 98. |
The process of shot peening increases the fatigue life of steel springs mainly because it results in |
| A. | surface hardening |
| B. | increased stiffness of the material |
| C. | structural changes in the material |
| D. | residual compression at the surface |
| Answer» E. | |
| 99. |
Stress concentration in a machine component of a ductile material is not so harmful as it is in a brittle material because |
| A. | in ductile material local yielding may distribute stress concentration |
| B. | ductile material has larger young's material |
| C. | Poisson's ratio is larger in ductile materials |
| D. | Modulus of rigidity is larger in ductile materials |
| Answer» B. ductile material has larger young's material | |
| 100. |
The outside diameter of a hollow shaft that is twice its inside diameter the ratio of its torque carrying capacity to that of a solid shaft of the same material and the same outside diameter is |
| A. | <table><tr><td style="border-bottom:1px solid #000000;vertical-align:bottom;padding-bottom:2px;"><center>15</center></td></tr><tr><td style="text-align: center;">16</td></tr></table> |
| B. | <table><tr><td style="border-bottom:1px solid #000000;vertical-align:bottom;padding-bottom:2px;"><center>3</center></td></tr><tr><td style="text-align: center;">4</td></tr></table> |
| C. | <table><tr><td style="border-bottom:1px solid #000000;vertical-align:bottom;padding-bottom:2px;"><center>1</center></td></tr><tr><td style="text-align: center;">2</td></tr></table> |
| D. | <table><tr><td style="border-bottom:1px solid #000000;vertical-align:bottom;padding-bottom:2px;"><center>1</center></td></tr><tr><td style="text-align: center;">16</td></tr></table> |
| Answer» B. <table><tr><td style="border-bottom:1px solid #000000;vertical-align:bottom;padding-bottom:2px;"><center>3</center></td></tr><tr><td style="text-align: center;">4</td></tr></table> | |