Machine Design Examination 9

1. For shafts, the shear due to bending is maximum at the neutral plane where the normal stress is:
A. Minimum B. Constant C. Maximum also D. Zero
2. The minimum value of numerical combined shock and fatigue factor to be applied in every case to the computed
bending moment of the shaft is:
A. 2.0 B. 1.75 C. 1.5 D. 1.3
3. What is the other name given to short shafts on machines?
A. Spindles B. Head shafts C. Core shafts D. All of these
4. What is the other name given to a line shaft?
A. Countershaft B. Main shaft C. Long shaft D. Head shaft
5. The speed at which the center of mass will be equal the deflecting forces on the shafts; the shaft with its
attached bodies will then vibrate violently, since the centrifugal force changes its direction as the shaft turns in:
A. Nominal speed B. Critical speed C. Relative speed D. Mean speed
6. An old rule of thumb for transmission shafting is that the deflection should not exceed _______ of length
between supports.
A. 0.01 in. per foot B. 0.08 in. per foot C. 0.02 in. per foot D. 0.05 in. per foot
7. For transmission shafts the allowable deflection is 1 degree in a length of ________ diameters.
A. 20 B. 25 C. 30 D. 40
8. What is the limiting torsional deflection for machinery shafts, if the criteria of limiting torsional deflection vary
from 0.08˚ per foot of length?
A. 1˚ B. 2.5˚ C. 2˚ D. 3.5˚
9. Bevel gears of sizes 5 in. to 15 in. should not be lift or depress more than _______, as Gleason statement.
A. 0.004 B. 0.003 C. 0.002 D. 0.001
10. What type of key that allows the hub to move along the shaft but prevents the rotation of the shaft?
A. Woodruff Key B. Feather Key C. Gibbs Key D. Square Key
11. What is the other name for Kennedy key?
A. Tangential key B. Woodruff key C. Saddle key D. Rollpin
12. What type of fits used for involute spline?
A. Close fit B. Press fit C. Sliding fit D. All of these
13. Which of the following is used for permanent fits and similar to involute splines except that the pressure angle is
14.5˚?
A. Separation load B. Spline shaft C. Stub serrations D. Involute serrations
14. It is used a coupling, or in addition to another couplings where, in case of overload, there is danger of injury to
machine or to material in process.
A. Shear pin B. Flange coupling C. Involute serrations D. King pin
15. What is the maximum shaft angle for a single Hooke’s coupling?
A. 10˚ B. 17˚ C. 15˚ D. 20˚
16. What are the two principal parts of a Journal Bearing?
A. Bearing and journal B. Shaft and babbit C. Clearance and fitted D. Shaft and cylinder
17. When the line of action of the load, bisects the arc of partial bearing, the bearing is said to be:
A. Eccentrically loaded B. Fully loaded C. Centrally loaded D. Partially loaded
18. What is the difference in radii of the bearing and Journal?
A. Even clearance B. Clearance ratio C. Odd clearance D. Radial clearance
19. When radii of both the bearing and the journal are the same, then the bearing is said to be:
A. Fitted bearing B. Clearance bearing C. Full bearing D. Ambiguous bearing
20. What is the line that passes through the centers of the bearing and the journals.
A. Line of action B. Line of centers C. Line of symmetry D. Tangent line
21. Which of the following is considered advantageous for bearing materials?
A. Conformability B. Compatibility C. Embeddability D. All of these
22. What is the recommended coefficient of fluctuation of flywheels for punching, shearing, pressing machine?
A. 0.005 – 0.1 B. 0.007 – 0.01 C. 0.03 – 0.05 D. 0.01 – 0.03
23. Which of the following considers the 200 series of bearing?
 A. Heavy B. Medium C. Light D. All of these
24. Which of the following considers the 300 series of bearing?
A. Heavy B. Medium C. Light D. All of these
25. A type of roller bearing in which the balls are assembled by the eccentric displacement of the inner ring.
A. Shallow groove ball gearing C. Self-aligning ball bearing
B. Filling-slot ball bearing D. Deep-groove ball bearing
26. Which of the following is not a type of ball bearing?
A. Shallow groove ball gearing C. Self-aligning ball bearing
B. Filling-slot ball bearing D. Deep-groove ball bearing
27. What is the usual density of the leather belt?
A. 0.035 lb/in³ B. 0.0135 lb/in³ C. 0.025 lb/in³ D. 0.0465 lb/in³
28. Which of the following is the approximate density of a fat rubber belt?
A. 0.055 lb/in³ B. 0.0135 lb/in³ C. 0.045 lb/in³ D. 0.0465 lb/in³
29. A toothed wheel whose tooth element are straight and parallel to the shaft axis or used to transmit motion and
power between parallel shafts.
A. Helical gear B. Spur gear C. Worm gear D. Bevel gear
30. The breaking strength of oak-tanned belting varies from 3 to more than:
A. 5 ksi B. 6 ksi C. 7 ksi D. 9 ksi
31. Experience suggests that the most economical designs are obtained for a belt speed of:
A. 6000 to 7500 fpm B. 3000 to 5000 fpm C. 3500 to 4700 fpm D. 5000 to 1000 fpm
32. The tension in the belt due to centrifugal force increasing rapidly above about:
A. 2500 fpm B. 3000 fpm C. 3500 fpm D. 4000 fpm
33. What is the recommended speed for leather belts?
A. 6000 to 7000 fpm B. 5000 to 6000 fpm C. 7000 to 8000 fpm D. 4500 to 5600 fpm
34. What is the usual recommended speed for fabric belts?
A. 4000 to 5000 fpm B. 3000 to 4000 fpm C. 2000 to 3000 fpm D. 2000 and more fpm
35. Which of the following is recommended initial tension of the belt?
A. 75 lb/in of width B. 73 lb/in of width C. 71 lb/in of width D. 80 lb/in of width
36. Two shafts at right angles to each other may be connected by what arrangement?
A. Half turn B. Quarter turn C. ¾ turn D. one turn
37. What is the minimum number of teeth on a smaller sprocket or low speed?
A. 12 B. 21 C. 17 D. 14
38. What is the minimum number of teeth on a smaller sprocket for moderate speed?
A. 17 B. 21 C. 12 D. 14
39. What is the usual minimum number of teeth on a smaller sprocket for high speed?
A. 21 B. 24 C. 12 D. 14
40. Which of the following is the measure of torsional stress?
A. Accuracy B. Stiffness C. Rigidity D. Precision
41. When tested in compression, ductile materials usually exhibit __________ characteristics up to the yield
strength as they do when tested in tension.
A. The same B. More than C. Less than D. Approximately the same
42. A tolerance where the size of a part is permitted to be either larger or smaller than the given dimension.
A. Bilateral B. Unilateral C. Lateral D. None of these
43. A fit generally used on those dimensions involved in a fit; such as pin in a hole.
A. Unilateral B. Lateral C. Bilateral D. None of these
44. It is relatively finely spaced irregularities of the surfaces.
A. Smoothness B. Waviness C. Lay D. Roughness
45. Which of the following is the surface finish of heavy cuts or coarse feed?
A. 200 rms B. 400 rms C. 80 rms D. 500 or greater rms
46. Which of the following is the most dominant cause (approximately 80%) of machine failures?
A. Torsion B. Negligence C. Fatigue failures D. Compression
47. For wrought steel in its commonly met commercial forms, it is often assumed that the average endurance limit
for an average Su (50% survival) with the Brinell Hardness is limited to:
 A. 500 B. 400 C. 240 D. 450
48. What is the range of the endurance ratio or Czaud quotes values for steel?
A. 0.23 to 0.65 B. 0.34 to 0.87 C. 0.63 to 0.93 D. 0.34 to 0.45
49. Which of the following indicates the degree of concentration?
A. Power factor B. Service factor C. Stress factor D. Stress concentration factor
50. The internal stresses that exist in any part of the material that is subjected to temperature and not acted upon
by an external load.
A. Residual stress B. Form stress C. Superposed stress D. Control stress
51. It is the process that cold works a limited amount of material, thus giving a higher strength, and it eaves a
surface compressive stress.
A. Surface finishing B. Tensioning C. Surfacing D. Surface rolling
52. Fatigue strength is increased by repeated loads just below the normal fatigue limit, followed by small step by
step increase of the loading.
A. Coaxing B. Triaxing C. Mixing D. Relieving
53. It is the diameter of the imaginary cylinder that bounds the crest of an external thread and the roots of an
internal thread.
A. Mean diameter B. Root diameter C. Stress diameter D. Major diameter
54. It is the distance in inches a screw thread (a helix) advances axially in one turn.
A. Pitch B. Mean pitch C. Lead D. Circular pitch
55. Which of the following bolts is recommended for general use?
A. UNC B. UNEF C. UNF D. NC
56. Which of the following is frequently used bolt in automobile and aircraft industries?
A. UNC B. UNEF C. UNF D. NC
57. Which of the following is a particular bolt used in aeronautical equipment?
A. UNC B. UNEF C. UNF D. NC
58. What type of bolt usually used for high-pressure pipe flanges, cylinder head studs etc.?
A. UNC B. UNF C. UNEF D. 8 UN
59. It is the stress or load induced by the tightening operation.
A. Initial stress B. Initial tension C. Residual stress D. None of these
60. For non-metallic gaskets, it has been found that they should have a certain minimum amount of compression as
______ for a certain cork gasket.
A. 62% B. 86% C. 68% D. 76%
61. It is a screw fastening with a nut.
A. Bolt B. U-bolt C. Rivet D. Screw
62. A fastening which has no nut and turns in to a threaded hole.
A. Bolt B. Fastener C. Rivet D. Screw
63. An old name for an unfinished through bolt comes with a square.
A. Coupling bolt B. Stud bolt C. Machine bolt D. Automobile bolt
64. It is a type of coil where the helical coil is wrapped into a circle forming an annular ring.
A. Volute spring B. Hair spring C. Motor spring D. Garter spring
65. It is a type of spring where thin flat strip wound up on itself as a plane spiral, usually anchored at the inside end.
A. Motor spring B. Garter spring C. Volute spring D. Helical spring
66. It is the ratio of the length of the column and the radius of gyration of the cross-section area about a centroidal
axis.
A. Contact ratio B. Slenderness ratio C. Centroidal ratio D. Column ratio
67. Under the theories of failure, for static loading of ductile material, the design stress is:
A. Yield stress/factor of safety C. Ultimate stress/factor of safety
B. Ultimate stress/Proportional limit D. Yield point/proportional limit
68. Under theories of failure, the value of shear test is how many times that of the tensile stress.
A. Four times B. Half C. Double D. One-fourth
69. The theory of mechanics of material shows that the results from a octahedral shear stress theory and those from
the maximum distortion-energy theory are:
A. The same B. Less than C. More than D. Not related
70. It is the distance measure axially from a point on one thread to the corresponding point on an adjacent thread.
A. Axial pitch B. Z-pitch C. Lead D. Lead angle
71. It is the angle between a tangent to the pitch helix and plane normal to the axis screw.
A. Helix angle B. Lead angle C. Tangent angle D. Vertical angle
72. It is suggested that the design factor on the yield strength be about 1.5 for the smooth load, about 2 to 2.25 for
minor shock loading, and up to ____ for severe shock loads, especially when the loading reverses during
operation.
A. 4.5 B. 3.5 C. 3.0 D. 4.0
73. A typical hub length fall between ________.
A. 1.25D to 2.5D B. 1.3D to 3.4D C. 1.25D to 4.0D D. D to 7.0
74. A key with one several patented methods of keying is driven or pressed into a hole that is small enough to close
the slit, assembled in radial direction.
A. Fit key B. Roll pin C. Saddle key D. Pin key
75. A key that allows the hub to move along the shaft but prevents the rotation of the shaft.
A. Woodruff key B. Gibs key C. Feather key D. Square key
76. For involute spline, the type of fits used:
A. Close fit B. Sliding fit C. Press it D. All of these
77. A coupling that transmit power via the frictional forces induced by pulling the flange toward each other over
slotted tapered sleeves.
A. Flange coupling C. Rigid coupling
B. Ribbed compression coupling D. Flanged compression coupling
78. A coupling used for absorbing some shock and vibration that may appear on one shaft and of preventing the
occurrence of reversed stresses caused by the shaft deflecting at the coupling preventing at the coupling.
A. Rigid coupling B. Flange coupling C. Flexible coupling D. None of these
79. It is the difference in the radii of the bearing and the journal.
A. Even clearance B. Clearance ratio C. Fit clearance D. Radial clearance
80. A bearing in which the radii of the journal and the nearing are the same.
A. Fitted nearing B. Full bearing C. Partial bearing D. Clearance bearing
81. What is the approximate length-to-diameter ratio of hydrodynamic bearings?
A. 1 B. 4 C. 3 D. 2
82. The operating temperature of oil films in the bearing must approximately:
A. 140℉ to 150℉ B. 140℉ to 160℉ C. 120℉ to 190℉ D. 120℉ to 190℉
83. At higher temperatures, oil oxidizes more rapidly above:
A. 120℉ B. 200℉ C. 140℉ D. 160℉
84. For thrust bearing, the speed at moderate operating condition is:
A. 50 < Vm > 200 fpm B. 50 < Vm > 250 fpm C. 50 < Vm > 220 fpm D. 50 < Vm > 250 fpm
85. If the ends are joined by wire lacing machine, the usual efficiency of joint is:
A. 100% B. 75% C. 85% D. 88%
86. On high speed centrifugal blowers, it has been observed that the arc of contact is reduced from 180˚ at the rest
to ______ in motion.
A. 100˚ B. 90˚ C. 95˚ D. 110˚
87. The recommended net belt pull for rubber belt is:
A. 11.34 lb/ply per inch of width C. 13.75 lb/ply per inch of width
B. 16.35 lb/ply per inch of width D. 20.34 lb/ply per inch of width
88. For minimum quietness, use sprockets with ________ or more teeth.
A. 21 B. 23 C. 25 D. 27
89. If two intersecting shafts are to be belt connected ________ guides pulleys are to be used.
A. 1 B. 2 C. 3 D. 4
90. Wire ropes are made from cold-drawn with _____ or more teeth.
A. 21 B. 23 C. 25 D. 27
91. A wire rope that the wires and strands are twisted in the opposite direction.
A. Long lay B. Perform C. Regular lay D. Lang lay
92. A wire rope that the wires and strand are twisted in the same direction.
 A. Long lay B. Perform C. Regular lay D. Lang lay
93. Which of the following ropes is used to haulage, rigging, guard rails.
A. 6 x 35 IWRC B. 6 x 15 IWRC C. 7 x 8 IWRC D. 7 x 7 IWRC
94. Which of the following has been considered as general purpose rope?
A. 6 x 19 IWRC B. 7 x 25 IWRC C. 7 x 25 IWRC D. 6 x 9 IWRC
95. Which of the following ropes is used for lines, hawsers, overhead cranes, and hoists?
A. 6 x 37 IWRC B. 6 x 35 IWRC C. 6 x 25 IWRC D. 7 x 26 IWRC
96. The regular materials for wire ropes that are made of:
A. Chromium B. Wrought iron C. Cast steel D. High-carbon iron
97. What is the minimum suggested design factor of wire ropes for miscellaneous hoisting equipment is:
A. 2 B. 3 C. 5 D. 4
98. To avoid excessive wear rate the recommended limiting pressure for 9 x 19 rope is ______ for cast steel.
A. 700 psi B. 900 psi C. 1000 psi D. 1200 psi
99. To avoid excessive wear rate the recommended limiting pressure for 9 x 19 rope is ______ for manganese cast
steel.
A. 2500 psi B. 2000 psi C. 3000 psi D. 2300 psi
100. What friction devices that are used to connect shafts?
A. Clutches B. Spring C. Brakes D. Holders