Mechanical Engineering Review Online

1. A shearing machine is used to crop off lengths of round bar 25 mm diameter. If the ultimate shear strength of the material is 180 MPa, determine the force needed to crop the bar.

a. 77.89

b. 68.37

c. 85.32

d. 88.36

2. The force of a point of a shaper when cutting is 1600 N. If the length of the stroke is 130 mm, how much work is done in one cutting stroke.

a. 200 J

b. 250 J

c. 208 J

d. 220 J

3. The shear strength of a plate is 280 MPa. Find the force required to punch a hole of 50 mm diameter in a plate 8 mm thick.

a. 300.2 kN

b. 351.9 kN

c. 377.2 kN

d. 385.2 kN

4. The shear strength of a shaft is not to exceed 45 MPa. The shaft is 110 mm. What is the greatest torque that can be applied on it?

a. 12662.35 kN-m

b. 11760.36 kN-m

c. 13790.35 kN-m

d. 10328.65 kN-m

5. Two shafts are connected by a flange coupling. The coupling is secured by 8 bolts, 20 mm in diameter on a pitch circle diameter of 180 mm. If the torque applied is 130 N-m, calculate the shear in the bolts.

a. 0.4382 MPa

b. 0.6873 MPa

c. 0.3581 MPa

d. 0.5747 MPa

6. The coefficient of friction depends on the materials of the pulley and the belt, on the slop, and on the belt speed. For leather belts on dry cast-iron or wood pulleys a recommended value of the coefficient of friction is:

a. 0.40 – 0.50

b. 0.30 – 0.40

c. 0.50 – 0.60

d. none of the above

7. The allowable stress for shafts carrying spur gear is

a. 8500 to 9000 psi

b. 5500 to 6000 psi

c. 6500 to 7000 psi

d. 7500 to 8000 psi

8. It is evident that the efficiency of a square-threaded screw depends on the lead angle. The efficiency therefore reaches a maximum value for a lead angle approximately equal to:

a. 40 deg

b. 45 deg

c. 30 deg

d. 35 deg

9. The use of large-diameter sheaves and the corresponding high belt speeds decrease the load on belts required to transmit the power, but the gain with belt speed is partly nullified by the:

a. Increase in centrifugal forces due to the high speeds 

b. Decrease in centrifugal force due to the low speeds

c. Increase in belt tensions due to the high speeds

d. none of the above

10. A thin hollow sphere of radius 12 in and thickness of 0.10 in is subjected to an internal pressure of 120 psi. The maximum normal stress on an element of sphere is:

a. 7200 psi

b. 7000 psi

c. 7300 psi

d. 7400 psi

11. Calculate the load, in kN on a 28 mm diameter by 1000 mm long steel shaft, if its maximum elongation will not exceed 1.0 mm.

a. 120.5

b. 127.5

c. 135.6

d. 115.2

12. How long will it take for a 50 mm length keyway to be milled if the milling machine has a 20 cutter turning at 140 rpm and feed rate of 0.130 mm per tooth?

a. 0.1025 min

b. 0.0987 min

c. 0.1374 min

d. 0.1627 min

13. In power transmission shafts, the torsional moment is usually in one direction and nearly steady so that fatigue notch factor for shear stress can be taken as:

a. Zero

b. Maximum

c. Minimum

d. Unity

14. This theory of failure states that inelastic action occurs when the maximum unit strain in any direction exceeds the unit strain at the tensile yield point for the material as determined in a pure tensile test.

a. Guest-Hancock theory

b. Rankine theory

c. Saint-Venant’s theory

d. All of the above

15. This theory states that inelastic action occurs when the distortion energy per unit volume of the material equals the distortion energy per volume for the material at tensile yield point as determined by a simple tension test.

a. James Clerk Maxwell theory

b. Hencky-Von Mises theory

c. Huber theory

d. All of the above

16. These are threaded members used to prevent angular rotation between a gear, pulley, sheave, collar or similar machine element and the shaft on which it is mounted.

a. Translation screws

b. Set screws

c. Power screws

d. All of the above

17. Recommended groove angles for V-belt sheaves are:

a. 32 to 38 deg

b. 34 to 40 deg

c. 35 to 42 deg

d. non of the above

18. Calculate the polar section modulus, in cu. inches of SAE 1060 shafting having a diameter of 3.5 inches. Used a factor of safety of 3 and design stress of 9000 psi.

a. 8.42

b. 5.32

c. 7.25

d. 6.28

19. What spindle speed, in rpm is required to produce a cutting speed of 160 fpm on a 2.5 in diameter bar?

a. 200.2

b. 244.5

c. 308.2

d. 158.3

20. A round steel shaft transmits 50 kW and rotates at 160 rad/s. Determine the angle of twist, in degrees for a 4 meters length shaft. The allowable shearing stress is 50 MPa and G=68 GPa.

a. 12.3

b. 10.6

c. 9.8

d. 15.3

21. The cutting speed of a tool passing thru 3.0-in diameter material at 280 rpm, is ____.

a. 210.9

b. 235.2

c. 255.3

d. 219.9

22. A shaft is subjected to a twisting moment of 4.3 kN-m. the shaft is steel having 85 GPa modulus of rigidity. The torsional shear stress, in MPa for a 80 mm circular shaft is ____.

a. 38.2

b. 48.3

c. 50.2

d. 42.8

23. This employs a slow-squeezing action that penetrates throughout the metal and produces a uniform metal flow. In hammer or impact forging, metal flow is a response to the energy in the hammer-work piece collision.

a. Press forging

b. Roll forging

c. Upset forging

d. All of the above

24. In this process, metal is compressively forced to flow through a suitably shaped die to form a product with reduced cross section.

a. Drawing

b. Extrusion

c. Forging

d. All of the above

25. It is encouraged by excessive tension in the bolts, particularly if service loads exceeds 50% of the yield stress at least for low alloy quenched and tempered steels.

a. Stress cracking

b. Crushing

c. Yielding

d. Wear

26. The included thread angle for ACME thread of a translation screw is:

a. 30 deg

b. 35 deg

c. 29 deg

d. 45 deg

27. A spur pinion rotates at 1900 rpm and transmits to a mating gear 60 HP. The pitch diameter is 7 in and the pressure angle is 14.5 deg, calculate the tangential load.

a. 550.5

b. 560.3

c. 532.2

d. 503.1

28. Calculate the line shaft diameter to transmit 30 HP at 320 rpm with torsional deflection of 0.08 deg per foot length. G=12,500,000 psi.

a. 3.2 in

b. 2.5 in

c. 1.3 in

d. 4.0 in

29. Compute the deflection of a 26 coils helical spring carrying a load of 150 kgs. The modulus of elasticity in shear of spring 100 GPa, outside diameter of 8 cm and wire diameter of 8 mm. The spring is squared and ground ends.

a. 257.5 mm

b. 268.3 mm

c. 235.2 mm

d. 276.3 mm

30. What is the working strength of 2-in bolt which is screwed up tightly in a packed joint when the allowable working stress is 12,000 psi?

a. 18020 lbs

b. 22500 lbs

c. 16310 lbs

d. 20400 lbs

31. The total weight of steel plate with size of 1” x 5’ x 25’ is ____.

a. 4221 lbs

b. 3218 lbs

c. 5112 lbs

d. 3012 lbs

32. A small shaft is 2.5-in diameter and has an allowable stress of 8000 psi. Find the horsepower delivered by the shaft at speed of 22 rad/sec.

a. 78.23

b. 85.31

c. 81.81

d. 75.31

33. The torsional deflection of steel shaft is 0.65 deg per meter length. The shear stress is 65 MPa. Calculate the diameter of the shaft, in mm. Steel modulus of elasticity is 80 GPa.

a. 132.2

b. 162.3

c. 143.2

d. 188.5

34. Calculate the diameter of a solid shaft transmitting 85 Hp at 1700 rpm. The allowable shear stress on pure torsion is 6500 psi.

a. 2.5 in

b. 1.4 in

c. 3.1 in

d. 4.5 in

35. A foot rule has how many 1/16 inch?

a. 192

b. 210

c. 160

d. 96

36. This type of lubrication occurs when the lubricant film is sufficiently thick to prevent the opposite solids from coming into contact

a. Hydrostatic lubrication 

b. Elastohydrodynamic lubrication

c. Hydrodynamic lubrication

d. none of the above

37. The distance from a point on one tooth to the corresponding point on the adjacent tooth measured on the pitch circle.

a. Circular pitch

b. Pitch

c. Diametral pitch

d. All of the above

38. A combination of natural or synthetic resins and drying oil, sometimes containing volatile solvents as well.

a. Varnish

b. Lacquer

c. Enamel

d. Paint

39. A M12 x 1.75 thread means:

a. Nominal diameter of 12mm and pitch of 1.75mm 

b. Nominal diameter of 12 mm and lead of 1.75 mm

c. Minor diameter of 12 mm and pitch of 1.75 mm

d. All of the above

40. At what temperature does aluminum melts, which makes it very desirable for the production of either permanent or sand-mold castings

a. 770 deg

b. 880 deg

c. 550 deg

d. 660 deg

41. Compute the safe wall thickness of a 100 cm diameter steel tank. The tank is subjected to 8 MPa pressure and the steel material has a yield stress of 250 MPa. Use factor of safety of 4.

a. 5.5 cm

b. 6.4 cm

c. 7.3 cm

d. 4.2 cm

42. The shaft is subjected to steady load of 35,000 lb at a shear stress of 13,000 psi. Calculate the diameter of the shaft, in inches.

a. 2.6

b. 3.8

c. 1.8

d. 4.1

43. A hollow shaft with outside diameter of 15 cm and wall thickness of 0.10 cm transmits 220 kW at 380 rpm. Calculate the angular deflection of the shaft if the length is 6 meters. G=12,000,000 psi.

a. 8.84 deg

b. 7.91 deg

c. 6.33 deg

d. 9.24 deg

44. A flywheel has a diameter of 1.8 m and a mass of 800 kg. What torque is needed to produce an angular acceleration of 100 rpm, per second?

a. 2690.92 J

b. 3392.92 J

c. 4028.71 J

d. 5511.11 J

45. Determine the power transmitted by 1-in short shaft rotating at 400 rpm.

a. 6.1 hp

b. 8.8 hp

c. 9.0 hp

d. 7.8 hp

46. What is the modulus of elasticity in tension is required to obtain a unit deformation of 0.00120 m/m from a load producing a unit tensile stress of 43000 psi?

a. 22.1x10⁶ psi

b. 18.7x10⁶ psi

c. 35.8x10⁶ psi

d. 40.1x10⁶ psi

47. If all the carbon in cast iron is in form of cementite and pearlite, with no graphite present, the resulting structure is:

a. Gray

b. White

c. Black

d. Brown

48. It should be remembered that if the screw is required to be self-locking, a _____ is necessary in order to introduce intentionally a frictional force that is sufficient to prevent reverse motion.

a. High lead angle

b. Low lead angle

c. High friction angle

d. Low friction angle

49. For most metals Poisson’s ratio lies in the range:

a. 0.40 to 0.50

b. 0.35 to 0.45

c. 0.25 to 0.35

d. 0.30 to 0.40

50. Which of the following is not a classification of alloy steels?

a. High-alloy

b. Medium carbon alloy

c. Medium alloy

d. Low alloy

51. A 2.0-in diameter by 4.5-in long journal bearing is to carry a load of 1200 lb at 1800 rpm using SAE 40 lube oil. Calculate the bearing pressure.

a. 120.3 psi

b. 133.3 psi

c. 153.1 psi

d. 110.8 psi

52. What force is required to punch 1-in hole on 3/4-in thick plate, if the ultimate shear strength on the plate is 43,000 psi?

a. 200382 lbs

b. 98328 lbs

c. 101316 lbs

d. 155111 lbs

53. Improves the machinability of alloy steels but affects different alloy steels differently:

a. Vanadium

b. Lead

c. Selenium

d. Manganese

54. Improves the hardenability economically, resistance to corrosion, strength at high temperature

a. Manganese

b. Chromium

c. Aluminum

d. Phosphorus

55. When steel castings are heat treated, the carbon content generally falls within the range of:

a. 0.20 to 0.30%

b. 0.15 to 0.20%

c. 0.60 to 0.90%

d. 0.25 to 0.50%

56. The most effective alloy in increasing toughness of steel

a. Nickel

b. Lead

c. Copper

d. All of the above

57. Two parallel shaft connected by pure rolling turn in the same direction and having a speed ratio of 5. What is the distance of the two shafts if the small cylinder is 8.5 cm?

a. 17 cm

b. 20 cm

c. 15 cm

d. 23 cm

58. If the pitch of a screw is 2/7, find the thread per inch.

a. 3.5

b. 4.0

c. 4.5

d. 2.5

59. Calculate the bursting steam pressure of a steel shell with diameter of 15-in and made of 1/4-in steel plate. The joint efficiency is 80% and the tensile strength is 60 ksi.

a. 3200 psi

b. 2800 psi

c. 4100 psi

d. 2000 psi

60. Increases the hardenability of alloy steels:

a. Manganese

b. Molybdenum

c. Phosphorus

d. All of the above

61. Martensite (stainless steel) contains 4 to 26% Cr and maximum of ____% nickel

a. 2.5

b. 4.5

c. 1.5

d. 3.5

62. The shaft that is used to connect or disconnect the drive at will is called:

a. Clutch

b. Brake shaft

c. Lock shaft

d. Bearing

63. The distance from a point on a screw thread to a corresponding point on the next measure along the axis:

a. Thickness

b. Pitch

c. Module

d. Radial

64. The ideal for maximum quietness in sprocket drive operation to choose ____ or more teeth.

a. 25

b. 26

c. 27

d. 28

65. In the SAE identification code of steel shafting the third and fourth digits represents the content of:

a. % manganese on the steel 

b. % chromium in the steel

c. % alloy elements

d. % carbon content

66. For a single universal joint, shaft angle should be ____ degrees maximum and much less if on high rotational speed.

a. 14

b. 16

c. 15

d. 12

67. Not part of the head stock:

a. Spindle

b. Back gear

c. Spindle

d. Anvil

68. Determine the tooth thickness of a 20 degree full depth involute tooth having a diametral pitch of 5.

a. 6.2 mm

b. 5.5 mm

c. 8.0 mm

d. 7.3 mm

69. A bolt has a tensile load of 280 lbs. The bolt is made of SAE 1040 material with Sy=55 ksi, what is the stress area of the bolt?

a. 0.0721 in²

b. 0.1213 in²

c. 0.0977 in²

d. 0.0813 in²

70. What is the pressure required to punch a hole 3.8-in diameter thru a 1/2-in steel plate?

a. 132 tons

b. 152 tons

c. 168 tons

d. 170 tons

71. A cylindrical tank with 12-in inside diameter contains air at 1900 psi. Calculate the required thickness under stress of 28,000 psi.

a. 8.3 mm

b. 10.3 mm

c. 12.1 mm

d. 15.8 mm

72. A 72 tooth pinion with a turning speed of 460 rpm drives 180 tooth gear of 14.5 degree involute angle. Find the speed necessary for the driven gear.

a. 184 rpm

b. 172 rpm

c. 155 rpm

d. 165 rpm

73. All four compression springs support one load of 800 g. All four springs are arranged in parallel and rated at 0.610 g/mm. Compute for the deflection, in mm

a. 327.9 mm

b. 301.1 mm

c. 280.2 mm

d. 381.8 mm

74. A body weighing 1200 lbs falls 8-in and strikes an 1800 lb per inch spring. The deformation of spring is ____.

a. 8/3 in

b. 4 in

c. 2 in

d. 5 in

75. A gear set having gear ratio of 4 is to be used at a center distance of 18 inches. If the gear has 80 teeth, what must be the circular pitch?

a. 32.7 in

b. 25.3 in

c. 28.7 in

d. 22.1 in

76. What is the allowable load, in pounds on a single strand roller chain used in tension linkage under steady load conditions if the standard pitch is 3/4-in?

a. 1068.75 lbs

b. 1321.82 lbs

c. 1552.31 lbs

d. 1631.91 lbs

77. What is the standard roller chain number for a driving speed of 1300 rpm?

a. 25

b. 80

c. 40

d. 60

78. In order to make allowance for the dynamic effect due to the velocity of tooth action, the Barth equation may be used. What will be the allowable stress, in psi if the basic stress is 12,000 psi and pitch-line velocity is 900 fpm.

a. 5000

b. 4800

c. 3200

d. 5400

79. Calculate the maximum permissible bore, in inches if the gear is to be keyed to a shaft when the pitch diameter is 3.2-in, pitch line velocity is 600 fpm, and the number of teeth is 20?

a. 2.5

b. 3.1

c. 2.0

d. 1.6

80. Determine the torque transmitted by the single block of a clutch if coefficient of friction is 0.2, radius of drum is 15-in, uniform pressure of 45 psi, width of block parallel to the axis of rotation is 4-in, angle of contact of 100 deg, and a speed of 280 rpm.

a. 13220.2 in-lb

b. 16021.1 in-lb

c. 18220.8 in-lb

d. 14137.2 in-lb

81. Determine the Wahl's factor for a mean coil diameter of 70 mm and wire diameter of 10 mm.

a. 2.2

b. 3.1

c. 1.2

d. 4.0

82. A helical coil spring has a mean diameter of 32 mm and a wire diameter of 5 mm. If the shearing stress is 420 MPa, how much load can it support?

a. 322.7 N

b. 653.8 N

c. 521.7 N

d. 492.1 N

83. In problem 83, how many coils would be needed to restrict the deflection to 30 mm under that load if the shear modulus of elasticity is 90 GPa?

a. 10

b. 15

c. 13

d. 18

84. Find the centrifugal force, in N for a leather belt with the following specifications: width=120 mm, thickness=6.5 mm, velocity=18.5 m/s, specific weight of belt material=980 kg/m³.

a. 351.8

b. 188.2

c. 408.2

d. 261.6

85. A round steel shaft rotates 210 rpm and is subjected to a torque of 230 N-m and a bending moment of 350 N-m. The allowable shearing stress is 50 MPa and the allowable tensile stress is 55 MPa. Determine the shaft diameter.

a. 32 mm

b. 48 mm

c. 41 mm

d. 28 mm

86. 1/4-in leather belt transmits 35 HP while running on 2.5 ft pulley rotating at 550 rpm. The allowable belt stress is 600 psi; angle of contact is 145 deg. Calculate the belt width, assuming coefficient of friction of 0.48.

a. 3.2 in

b. 2.9 in

c. 4.0 in

d. 2.1 in

87. An impact test is used to test a metal for:

a. Toughness

b. Hardness

c. Ductility

d. Strength

88. A simple disc clutch has elements outside and inside diameters of 280 mm and 120 mm, respectively. The axial force is 1000 N. If the coefficient of friction is 0.40, find the torque capacity based on uniform pressure.

a. 48.3 N-m

b. 42.1 N-m

c. 55.3 N-m

d. 62.1 N-m

89. In problem 88, calculate the torque capacity based on uniform wear theory.

a. 40 N-m

b. 50 N-m

c. 60 N-m

d. 30 N-m

90. Compute the diameter of a solid, in inches shaft that rotates 120 rpm and transmits 1.5 HP. The design stress for shear is to be 6500 psi and the shaft is subjected to torsion only.

a. 0.8514

b. 0.7032

c. 0.6011

d. 0.5103

91. Calculate the diameter of shaft for which torsional deflection will not exceed one degree in a length of 25 diameters. The shaft is to transmit 45 HP at 220 rpm. Assume that the shear modulus of elasticity is 11.5 x 106 psi.

a. 3.5 in

b. 4.2 in

c. 1.0 in

d. 2.5 in

92. Two extension springs are hooked in series and support a load of 130 lbs. One spring has a spring constant of 60 lb/in and the other has a spring constant of 110 lb/in. What is the deflection of the load?

a. 4.2 in

b. 5.8 in

c. 6.1 in

d. 3.3 in

93. In problem 92, if these springs were place in parallel, what would be the deflection?

a. 0.71 in

b. 0.55 in

c. 0.41 in

d. 0.81 in

94. Specify the diameter of a round column 1.8 m long which is to carry a maximum load estimated to be 25 kN. Use a design factor of 5 and consider the ends as pinned (rounded). The column material selected has minimum yield strength of 480 MPa and a modulus of elasticity of 200 GPa.

a. 44.83 mm

b. 38.21 mm

c. 50.00 mm

d. 40.17 mm

95. A square thread power screw has a major diameter of 35 mm and a pitch of 5 mm with double threads. Determine the torque required to rotate the screw against the load. Diameter of collar=43 mm, coefficient of friction for both thread and collar is 0.09, force, F = 6.5 kN/screw.

a. 9.8 N-m

b. 12.6 N-m

c. 14.8 N-m

d. 15.7 N-m

96. In problem 95, determine the torque required to rotate the screw with the load.

a. 18.3 N-m

d. 15.7 N-m

c. 12.6 N-m

d. 13.4 N-m

97. Two metric spur gears are engaged. The ratio is 3/2 and they have a module of 2.0 mm. Find the number of teeth for each gear if the center distance is 130 mm.

a. 65

b. 60

c. 78

d. 82

98. A cast-iron flywheel has a rim thickness of 3/4-in and width of 12 -in. The mean diameter is 40-in. Assuming the arms and hub amount to be one eight of the rim weight and the speed regulation must be kept with in 12% of the normal operating speed. Average velocity is 90 ft per sec, compute the capacity of the flywheel.

a. 6682 ft-lb

b. 9985 ft-lb

c. 7321 ft-lb

d. 5211 ft-lb

99. A cast-iron flywheel has a mean diameter of 40-in and rotational speed of 380 rpm. Find the hoop stress.

a. 426.2 psi

b. 328.1 psi

c. 550.2 psi

d. 289.1 psi

100. The modulus of elasticity (tension) of a material is 220 GPa and the transverse modulus of elasticity (shear) is 85 GPa. Determine the Poisson's ratio.

a. 0.1984

b. 0.8891

c. 0.6108

d. 0.2941