Mastery Exam in Machine Design
1.
2.
3.
With the water interruptions prevailing in your town, you have been asked to design an
upright cylindrical water tank 6 meters in diameter and 6 meters high, vented, and to be
filled completely with water. Determine the minimum thickness of the tank plate if the
stress is limited to 40 Mpa.
a) 3.3 mm
b) 4.4 mm
c) 5.5 mm
d) 8.8 mm
A steel shaft 1.75 inches in diameter transmits 40 Hp at 1800 rpm. Assuming a modulus of
rigidity of 12 x 106 psi, find the torsional deflection of the shaft in degrees per foot
length.
a) 0.0073
b) 0.0037
c) 0.0063
d) 0.00013
A double thread ACME screw driven by a motor at 400 rpm raises the attached load of 900 kg
at a speed of 10 m/min. The screw has a pitch diameter of 36 mm; the coefficient of friction
on threads is 0.15. The friction torque on the thrust bearing of the motor is taken as 20
% of the total input. Determine the lead angle.
a) 12.465o
b) 14.265o
c) 15.462o
d) 16.452o
4. A cylinder having an internal diameter if 508 mm and external diameter if 914.4 mm is
subjected to an internal pressure of 69 MPa and an external pressure of 14 MPa. Determine
the hoop stress at the inner surface of the cylinder.
a) 90.11 MPa
b) 91.10 MPa
c) 911.0 MPa
d) 19.10 Mpa
5. What length of a square key is required for a 4-in diameter shaft transmitting 1000 hp at
1000 rpm? The allowable shear and compressive stresses in the key are 15 ksi and 30 ksi,
respectively.
a) 2.1 inches
b) 2.8 inches
c) 3.2 inches
d) 4.2 inches
6. Which of the following are the compositions of stainless steel 302?
a) 18 % chromium and 8 % nickel
b) 18 % nickel and 8 % chromium
c) 18 % chromium and 8 % phosphor bronze
d) 18 % bronze and 8 % vanadium
7. A single square thread power screw is to raise a load of 70 kN. The screw has a major
diameter of 36 mm and a pitch of 6 mm. The coefficient of thread friction and collar
friction are 0.13 and 0.10 respectively. If the collar mean diameter is 90 mm and the
screw turns at 60 rpm, find the combined efficiency of the screw and collar.
a) 15.32 %
b) 12.53 %
c) 13.52 %
d) 15.97 %
8. A 50-mm diameter shaft is to transmit 12 kW power at a speed of 500 rpm, determine the
mean diameter of the pin, under double shear, for a material having a safe unit stress of
40 N/mm2.
a) 11.08 mm
b) 12.08 mm
c) 13.08 mm
d) 10.08 mm
9. A 1200 mm cast iron pulley is fastened to 112.5 mm shaft by means of a 28.13 mm square
key 175 mm long. The key and shaft have a shearing stress of 14 000 psi. Determine the
force acting at the pulley that will shear the key.
a) 10 015 lb
b) 11 005 lb
c) 11 050 lb
d) 10 501 lb
10. A 75-mm diameter shaft is transmitting 350 kW at 650 rpm. A flange coupling is used and
has 6 bolts, each 18 mm in diameter. Find the required diameter of the bolts circle based
on an average shearing stress of 27.5 MPa.
a) 245 mm
b) 254 mm
c) 452 mm
d) 425 mm
11. In estimating the actual endurance strength of steel parts, one of the factors to be
considered is the material factor, which of the following is the recommended material
factor for cast steel?
a) 0.70
b) 0.80
c) 0.75
d) 1.0
12. If stiffness is the main criterion in selecting a material, which of the following is the
most economical choice?
a) SAE 3130
b) SAE 1020
c) SAE 6150
d) AISI 301, ¼ hard
stainless steel
13. A stepped torsion shaft has diameters of 16 mm and 12 mm and a fillet radius of 2 mm. The
shaft is subjected to a torque of 12.5 N-m. Find the maximum induced stress caused by the
fillet. Consider a stress concentration factor of 1.25.
a) 36.84 MPaa
b) 46.05 MPa
c) 38.64 MPa
d) 45.06 MPa
14. A parallel helical gear-set consists of a 19-tooth pinion driving a 57-teeth gear. The
pinion has a left-hand helix angle of 20o, a normal pressure angle of 14½o, and a normal
diametral pitch of 10 teeth/inch. If the pinion is to transmit 50 Hp at a speed of 1750
rpm. Determine the center distance of the two gears.
a) 2.02 inches
b) 6.06 inches
c) 4.04 inches
d) 2.06 inches
15. A coupling that allows axial flexibility/movement in the operation. Made of alternate
bolting of steel, leather, fabric and/or plastic material into two flanges.
a) Flexible disk coupling
b) Flexible toroidal spring coupling
c) Flexible Oldham coupling
d) Elastic material bonded coupling
16. Which of the following is not true for an instant center or centro of planar linkages?
a) Centro is a point common to two bodies having the same velocity in each.
b) Centro is a point in one body about which another body does not rotate.
c) Centro is a point in one body about which another body actually turns.
d) Centro is a point in one body about which another body tends to turn.
17. Select a deep-groove ball bearing to carry a radial load Fx = 800 lb and a thrust load Fz
= 700 lb at 1800 rpm. The service is 8 hr/day, but it is not continuous; design for 18
250 hr. The operation is smooth with little vibration; the outer ring rotates. Determine
the design life in million revolution (mr) with no more than 10 % failure.
a) 1791 mr
b) 1971 mr
c) 1197 mr
d) 1917 mr
18. Determine the radius of gyration of a wheel that has an outside and inside diameters of 1
meter and 0.75 meter, respectively? Neglect its hub and arms.
a) 0.5125 m
b) 0.6125 m
c) 0.3125 m
d) 0.4125 m
19. Determine the tensile stress area of an American Standard Screw Threads 6-32 UNC with
basic major diameter of 0.1380 inch.
a) 9.085 x 10-3 in2
b) 9.085 x 10-2 in2
c) 9.085 x 10-4 in2
d) 9.085 x 10-5 in2
20. What is the number of threads per mm and the tensile stress area of a standard Metric
screw Thread designated by M10 x 1.5?
a) 0.555 and 57.99 mm2
b) 0.667 and 57.99 mm2
c) 1.5 and 57.99mm2
d) 1.75 and 57.99 mm2
21. What is the difference of the values of the Wahl factor and the Bergstrasser factor, in
percentage?
a) 1 %
b) Less than 1 %
c) Greater than 1 %
d) 0.5 %
22. When the pitch line speed is above 8000 fpm, the teeth should be _____.
a) Ground after hardening
b) Should be cooled in air
c) Should not be quenched after hardening`
d) none of these
23. A 500 mm brake drum has a simple brake that is to absorb a torque of 250 N-m. If the
coefficient of friction and the contact angle between the band and drum are 0.2 and 180º,
respectively, and that the length of the brake arm is twice the drum diameter, determine
the minimum braking force applied at the free end of the brake arm.
a) 721.5 N
b) 752.1 N
c) 275.1 N
d) 572.1 N
24. 222.449 kN of tensile load is applied to a round bar made from SAE 1025 low carbon
steel. Using a factor of safety of 4 and assuming that the stress concentration factor
is 1.45, what is the required outside diameter in mm of the member if the ratio of the
inside and outside diameter is 0.75? For the material, the yield strength is 276 MPa.
a) 283.34
b) 116.64
c) 98.76
d) 156.54
25. A ¾ inch thick steel plate is to punch for a 1-in diameter hole every 10 sec. The actual
punching takes 1 sec. The ultimate shear strength of the plate is 60,000 psi. The
flywheel of the punch press has a mass moment of inertia of 500 in-lb-sec2 and rotates at
a mean speed of 150 rpm. What is the speed fluctuation, in rpm?
a) 65.4 rpm
b) 64.5 rpm
c) 6.749 rpm
d) 67.49 rpm
26. A disc clutch is made of a material with coefficient of friction of 0.4. The shaft speed
is 1200 rpm and axial force is 1500 N. The clutch has 6 pairs of contacting friction
surfaces with an outside diameter of 200 mm and an inside diameter of 100 mm. Determine
the Hp that can be transmitted by the clutch assuming uniform pressure.
a) 35.2 Hp
b) 23.5 Hp
c) 47.2 Hp
d) 27.4 Hp
27. A tempered steel spring is used in a gas engine valve with a mean diameter of 3.81 cm and
a wire diameter of 0.635 cm. The maximum load it will have to sustain is 45.15 kg with
corresponding deflection of 1.27 cm. Determine the no. of coils to be used. Use modulus
of rigidity equal to 80 GPa.
a) 7.4
b) 8.1
c) 10.4
d) 14.4
28. Determine the kinetic energy of a 48-inch diameter spoked steel flywheel (γ = 0.28 lb/in3)
having a 12-in wide x 10-in deep rim rotates at 200 rpm. Neglect the weight of its spokes
and hub.
a) 84,448 ft-lb
b) 68,488 ft-lb
c) 42,248 ft-lb
d) 53,123 ft-lb
29. A disc clutch having an outside diameter of 32 cm and an inside diameter of 12.7 mm is
connected to an engine that turns at 750 rpm. The coefficient of friction is 0.6 while
the pressure between the friction surfaces is 2 kg/cm2. Determine the force on the clutch
petal necessary to disengage the clutch disc from the engine.
a) 2621.7 kg
b) 3248.4 kg
c) 2524.2 kg
d) 1355.1 kg
30. For a bolted connection, specification suggests that a high grade material of 13 mm bolt
be tightened to an initial tension of 55 000 N. What is the appropriate tightening
torque?
a) 134 N-m
b) 143 N-m
c) 341 N-m
d) 431 N-m
31. A carbon steel UNC bolt has a stress area of 0.606 in2, determine its permissible working
stress.
a) 4055.49 psi
b) 4505.49 psi
c) 4550.49 psi
d) 4455.09 psi
32. A 75 lb disc is mounted midway a 1-inch diameter shaft supported by bearings 20 inches
apart. Find the lowest critical speed in rpm. Neglect the weight of the shaft. Assume
that the modulus of elasticity is 30 000 000 psi.
a) 5763.43 rad/s
b) 301.77 rad/s
c) 1207.09 rad/s
d) 401.77 rad/s
33. A shaft is made of a material that weighs 0.28 lb/in3 and a modulus of elasticity of 30 x
106 psi. Bearings, 90 inches apart, support the 2-inch shaft that carries no rotating
disc. The shaft has a uniform cross section. Find the second critical speed, in rpm.
a) 4217.28 rpm
b) 4172.28 rpm
c) 4228.17 rpm
d) 4712.28 rpm
34. A 2-foot pulley rotating at 600 rpm carries a ¼-inch thick belt that transmits 30 Hp of
power. The allowable belt stress is 500 psi; the angle of contact is 150o. Find the belt
width required, assuming the coefficient of friction is 0.4 and the specific weight of
the belt material is 0.035 lb/in3.
a) 2.61 inches
b) 3.61 inches
c) 4.61 inches
d) 5.61 inches
35. Find the total torque necessary to raise the load of 3000 lb using a triple-thread square
power screw. The power screw has a root diameter of 2 inches and 2 threads per inch. It
is used in conjunction with a collar with an outer diameter of 4 inches and an inner
diameter of 2.5 inches. The coefficient of friction is 0.2 for both threads and collar.
a) 2445 lb
b) 2544 lb
c) 2454 lb
d) 4245 lb
36. A steel rod of 6 inches long is to resist an impact load of 500 lb dropped through a
distance of 2 inches. If the maximum computed stress is to be 20 ksi, determine the
required diameter of the rod.
a) 5.65 inches
b) 6.55 inches
c) 4.65 inches
d) 6.45 inches
37. A 40 kg load falls through a height of 0.20 m before striking the free end of a
cantilever beam. The beam is 60 mm wide and 100 mm deep. Compute the maximum bending
stress and deflection caused by the impact. Neglect the mass of the beam and assume that
the 40 kg mass remains in contact with the beam.
a) 162 MPa
b) 261 MPa
c) 126 MPa
d) 621 MPa
38. Determine the depth of the ACME thread if the pitch is 1.25 inches.
a) 0.625 inch
b) 0.635 inch
c) 1.25 inches
d) 0.750 inch
39. There are three parallel shafts A, B, and C. Shaft A has 24 teeth gear of Pd = 4 meshing
with a larger gear on shaft B having 70 teeth. A smaller gear, 20 teeth and pitch of 3,
on shaft B meshes with 50 teeth gear on shaft C. Find the torque on shaft C if the input
Hp to shaft A is 50 Hp turning at 1200 rpm, and the efficiency of each gear combination
is 98 %.
a) 1532 ft-lb
b) 1352 ft-lb
c) 1253 ft-lb
d) 1325 ft-lb
40. A ¾ inch thick steel plate is to punch for a 1-in diameter hole every 10 sec. The actual
punching takes 1 sec. The ultimate shear strength of the plate is 60,000 psi. The
flywheel of the punch press has a mass moment of inertia of 500 in-lb-sec2 and rotates at
a mean speed of 150 rpm. What is the speed fluctuation, in rpm?
a) 65.4 rpm
b) 64.5 rpm
c) 6.749 rpm
d) 67.49 rpm
41. A centrifugal pump discharges 3000 liters per minute at a head of 10 meters. The pump is
driven by a motor and pump efficiency is 68%. The pump rotates at 550 rpm. Find the
torsional stress of shaft if shaft diameter is 35mm.
A. 13.85 MPa
B. 11.85 MPa
C. 12.85 MPa
D. 14.87 MPa
42. Two shafts, made of the same materials, are circular in construction. One is hollow and
the other is solid. The hollow shaft inside diameter is one-half of the external
diameter. The external diameter is equal to the diameter of the solid shaft. What is the
ratio of the twisting moment of the hollow shaft to that of the solid shaft?
A.1/4
B. 1/3
C. 9/16
D. 15/16
43. A hollow shaft with an outside diameter of 100 mm is subjected to a maximum torque of
5,403.58 N.m. Determine its thickness if it not to exceed a shearing stress of 60 MPa or
a twist of 0.5 degree per meter length of shaft. G=83,000 MPa.
A. 15 mm
B. 86 mm
C. 16.8 mm
D. 14.2 mm
44. An oil storage tank roof formed to approximately a spherical surface, supported only at
its periphery.
a) Self-supporting umbrella roof
b) Self-supporting cone roof
c) Self-supporting
d) Supported cone roof
45. As suggested by Taylor, what is the recommended initial tension of belT?
a) 75 lb/in of width
b) 71 lb/in of width
c) 73 lb/in of width
d) 80 lb/in of width
46. It is considered as the best general-purpose deoxidizer.
a) Silicon
b) Titanium
c) Tungsten
d) Phosphorus
47. It is used for stabilizing austenitic stainless steels.
a) Silicon
b) Titanium
c) Tungsten
d) Phosphorus
48. It is an expensive alloy used for high-speed tools steel which forms abrasion-resisting
carbide.
a) Silicon
b) Titanium
c) Tungsten
d) Phosphorus
49. It improves machinability of free-cutting steels.
a) Silicon
b) Titanium
c) Tungsten
d) Phosphorus
50. It is a tin based and considered the best general-purpose bearing material.
a) Babbit
b) Hastelloy B
c) Zamaks
d) Stellites
51. Which of the following safety precautions should be followed when pouring Babbitt?
a) operator must wear goggles
b) the surface to be babbitted must be free of moisture
c) the surface to be babbitted must be clean
d) all of the above
52. Accuracy of a measuring instrument is:
A) Its capability to indicate the same reading again and again of a job
B) The smallest value that can be measured with its use
C) The closest reading to its true size
D) The closeness of reading that can be taken with it
53. The working temperature range for soldering process in degree Celcius is:
A) 60 C to 120 C
B) 180 C to 250 C
C) 220 C to 300 C
D) 350 C to 480 C
54. The size by which it is referred to as a matter of convenience called:
A)
actual size
B) basic size
C) effective size
D) nominal size
55. A tool bit for cutting an American National thread should be ground with a:
A) 45 deg. angle
B) 90 deg. angle
C) 60 deg. angle
D) 30 deg. Angle
56. Tapered shanks are used on large drill presses so that:
A) the drill can be centered more easily
B) the drill can be easily forced out of the sleeve with a drift
C) the shank will not turn when cutting
D) the shank can be reground when worn
57. A product of paddling furnace which contains less than 0.104 carbon, is called
A) cast iron
B) gray cast iron
C) pig iron
D) wrought iron
58. An alloying element which reduces deformation of configuration and sulfuric brittleness.
A) molybdenum
B) manganese
C) nickel
D) chromium
59. Heating of metal above the critical temperature and then cooling slowly usually furnace
to reduce the hardness and improve the machinability is called:
A) normalizing
B) tempering
C) annealing
D) quenching
60. It is a metal of almost pure iron, ductile and very tough. It can be hammered and shaped
at high temperature. It has a fibrous structure because of the presence of slag.
A) Nodular iron
B) Malleable iron
C) Wrought iron
D) Gray iron
61. A grinding wheel, which has got the marking “C”, is made with made with what abrasive?
A) Aluminum oxide
B) Silicon carbide
C) Aluminum
D) Steel
62. Steel springs are made of high carbon steel heat treated and/or cold worked to a high
elastic limit to get good elastic deflection. In general, the carbon content is at
_________.
A) 0.40% or more
B) 0.5% or more
C) 0.65% or more
D) 0.66% or more
63. In a chain drive design for large speed reduction it is preferable to use a double
reduction or compound type of transmission instead of single two sprockets transmission.
Drives should type be so designed that the angle between two tight chain strands does not
exceed_____degrees.
A) 45
B) 55
C) 60
D) 90
64. The welded joints permit placing the added metal exactly where needed and produce an
integral structure which can develop_____% efficiency on any thickness of section
specially for mild steel materials
A) 95%
B) 100%
C) 85%
D) 90%
65. The helical and herringbone gear teeth cut after heat treatment should have a hardness in
the range of 210/300 BHN. The pinion gear teeth hardness, on the other hand
ideally/normally should be at______BHN
A) 250/320
B) 400
C) 350/380
D) 340/350
66. As a rule, the center-to-center distance between sprocket should not be less than____
times the diameter of the bigger sprocket and not less than 30 times the pitch nor more
than about 50 times to pitch
A) 2.5
B) 3
C) 2
D) 1.5
67. For better mounting of bearing, it is preferred to heat the inner ring the range of 200degree F and___ but never more than______ F as overheating might reduce the ring hardness
A) 280
B) 300
C) 250
D) 320
68. To avoid scoring in the bearing surface and the shaft due to contamination/absorption of
the fine dirt in the bearing during operation/lubrication, the bearing material to apply
should have good _____properties
A) corrosion resistance conformability
B) embeddability
C) corrosion resistance
D) anti-scoring
69. A steel shaft transmits 40 Hp at 1400 rpm. Considering allowable shearing stress based on
pure torsion to be 5000 psi, find the torsional deflection of the shaft in degrees per
foot.
A) 0.392 degrees/foot
B) 0.541 degrees/foot
C) 0.246 degrees/foot
D) 0.435 degrees/foot
70. What is the difference between a shaper and a planer?
A) the tool of the shaper moves while on the planer is stationary
B) the shaper can perform slotting operation while the planer cannot
C) the shaper handles large pieces while the planer handle only small pieces
D) the tool of the shaper moves in reciprocating motion while the tool in the planer moves
in rotary motion
71. Two shafts are connected by spur gears. The pitch radii of gears A and B are 100 mm and
500 mm respectively. If shaft A makes 800 rpm and is subjected to a resisting torque of
113 N – m . What is the torque in shaft B?
A) 375 N-m
B) 565 N-m
C) 495 N-m
D) 690 N-m
72. The approximate hardness of HSS end mill cutter is
A) 45 HRC
B) 52 HRC
C) 62 HRC
D) 72 HRC
73. A polygon with 9 flats is to be milled using the indexing head. The indexing head
transmission ratio is 40:1. Determine the number of crank rotations.
A) 9 full rotations
B) 5 full rotation, 2 holes on the 36-hole circle.
C) 4 full rotation, 12 holes on the 27-hole circle.
D) 2 full rotation, 16 hole on the 47-hole circle.
74. Also called eccentrically loaded bearing is ________.
A) full bearings
B) partial bearing
C) offset bearing
D) fitted bearings
75. In the selection of wire rope, regular lay means wires and strands are arranged in the
following manner:
A) twisted in the same direction
B) twisted in opposite direction
C) twisted in any direction
D) twisted in along direction
76. The use of hardened steel for the mating metal gear appears to give the best results and
longer operational life. The usual hardness is in the range of
A) over 600 BHN
B) below 350 BHN
C) 300 to 400 BHN
D) over 400 BHN
77. When a column is subjected to an eccentric load, the stress induced in the column will
be?
A) Direct stress only
B) Bending stress only
C) Shear stress only
D) Direct and bending stress both
78. In riveted boiler joints, all stresses, shearing, bearing and tensile are based on the
A) Size of rivet
B) Size of the drilled or reamed hole
C) Average of size of rivet and hole
D) Smaller of the two
79. The binding material used in cemented carbide tools is
A) Tungsten
B) Chromium
C) Silicon
D) Cobalt
80. The operation of smoothing and squaring the surface around a hole is known as
A) Countersinking
B) Counter-boring
C) Trepanning
D) Spot facing
81. A coarse-grained grinding wheel is used to grind
A) Hard and brittle materials
B) Soft and ductile materials
C) Hard and ductile materials
D) Soft and brittle materials
82. A closely coiled helical spring is cut into two halves. The stiffness of the resulting
spring will be
A) Same
B) Double
C) Half
D) One-fourth
83. Which one of the following is a positive drive?
A) V-belt drive
B) Rope drive
C) Crossed flat belt drive
D) Chain drive
84. A steel containing up to 0.15% carbon is known as
A) Mild steel
B) Dead mild steel
C) Medium carbon steel
D) High carbon steel
85. Which of the following statement is FALSE?
A) The V-belt may be operated in either direction with tight side of the belt at the top or
bottom.
B) The V-belt drive is used with large center distance
C) The power transmitted by V-belts is less than flat belts for the same coefficient of
friction, arc of contact and allowable tension in the belts
D) The ratio of driving tensions in V-belt drive is more than flat belt drives
86. Cold working
A) Increases the fatigue strength
B) Decreases the fatigue strength
C) Has no influence on fatigue strength
D) Alone has no influence on fatigue strength
87. The shock resistance of steel is increased by adding
A) Nickel
B) Chromium
C) Nickel and chromium
D) Cobalt and molybdenum
88. Stress concentration factor is defined as the ratio of
A) Maximum stress to the endurance limit
B) Nominal stress to the endurance limit
C) Maximum stress to the nominal stress
D) Nominal stress to the maximum stress
89. In the calculation of induced shear stress in helical springs, the Wahl's stress factor
is used to take care of
A) Combined effect of transverse shear stress and bending stress in the wire
B) Combined effect of bending stress and curvature of the wire
C) Combined effect of transverse shear stress and curvature of wire
D) Combined effect of torsional shear stress and transverse shear stress in the wire
90. In a butt welded joint, the size of weld is __________ the throat of weld.
A) 0.5 times
B) Equal to
C) 2 times
D) Double
91. The groove angle of pulleys for V-belt is
A) 34° to 36°
B) 42° to 45°
C) More than 45°
D) 30° to 32°
92. Which of the following is not correct procedure to increase the fatigue limit?
A) Cold working
B) Shot peening
C) Surface decarburization
D) Under stressing
93. It is an age hardenable wrought alloy which has mechanical properties comparable to those
of heat-treated alloy steel of the same order of hardness and resistance to corrosion
like that of monel. What is this alloy of nickel?
A. R-Monel
B. K-Monel
C. Hastelloy
D. KR Monel
94. A thermomechanical heat treatment in which austenite is plastically deformed below the A1
temperature, then permitted to transform to bainite or martensite.
A. Ausforming
B. Austempering
C. Martensiting
D. Batensiting
95. In sulfuric acid, which of the following is suitable for handling acids in concentrations
up to 50% and at a temperature including boiling point?
A. Hastelloy A
B. Hastelloy B
C. Monel
D. Eutectoid
96. What accounts for the backlash of spur gears?
A. Pitch velocity
B. Radial velocity
C. Both pitch and module velocity
D. Both pitch and radial velocity
97. It has a zero coefficient of heat expansion, used for measuring instruments. It also an
alloy of iron with 30% nickel
A) Invar
B) Dynavar
C) Inconel
D) R-Monel
98. It is composed of 60% copper and 40% zinc, used for saltwater corrosion resistance and as
lining on boats.
A) Zurak Metal
B) Marzuk Metal
C) Alloying steel
D) Carburator
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