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CAT - Machine Design 1000+ MCQ [Solved] PDF Download

Thursday 9th of March 2023

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1. Which process will increase the fatigue duration of parts?
A. Finishing and polishing
B. Shotpeening
C. De-carburisation
D. Electroplating
Answer : B
2. A compound cylinder with inner radius 50 mm and outer radius 70 mm is made by shrinking one cylinder on to the other cylinder, the junction radius is 60 mm and the junction pressure is 1.1 N/mm². The maximum hoop stress developed in the inner cylinder is
A. 3.6 N/mm² compression
B. 3.6 N/mm² tension
C. 7.2 N/mm² compression
D. 7.2 N/mm² tension
Answer : C
3. Which of the following statement is correct for gears?
A. The pitch circle diameter is equal to the product of module and number of teeth
B. The addendum is less than dedendum
C. The pitch circle is always greater than the base circle
D. All of the above
Answer : D
4. The taper on cotter varies from
A. 1 in 24 to 1 in 20
B. 1 in 15 to 1 in 10
C. 1 in 32 to 1 in 24
D. 1 in 48 to 1 in 24
Answer : D
5. The most important dimension in the design of a nut is
A. Pitch diameter
B. Inside diameter
C. Outside diameter
D. Height
Answer : D
6. Whether any core is required in wire ropes
A. Yes
B. No
C. Sometimes
D. Rarely
Answer : A
7. A stud
A. Has a head on one end and a nut fitted to the other
B. Has head at one end and other end fits into a tapped hole in the other part to be joined
C. Has both the ends threaded
D. Has pointed threads
Answer : C
8. Eulers formula for a mild steel column is not valid if the slenderness ratio is
A. 90
B. 60
C. 120
D. 100
Answer : B
9. In standard taper roller bearings, the angle of taper of outer raceway is
A.
B.
C. 15°
D. 25°
Answer : D
10. Crowning on pulley helps
A. In decreasing the slip of the belt
B. In increasing the slip of the belt
C. To keep the belt in centre on a pulley while it is in motion
D. To increase pulley life
Answer : C
11. The ball bearings are provided with a cage
A. To reduce friction
B. To facilitate slipping of balls
C. To prevent the lubricant from flowing out
D. To maintain the balls at a fixed distance apart
Answer : D
12. Creep in belt is due to
A. Material of the belt
B. Material of the pulley
C. Uneven extensions and contractions due to varying tension
D. All of the above
Answer : C
13. Pick up wrong statement. Fatigue strength can be increased by
A. Cold working
B. Shot peening
C. Grinding and lapping surface
D. Hot working
Answer : D
14. Basic shaft is one
A. Whose upper deviation is zero
B. Whose lower deviation is zero
C. Whose lower as well as upper deviations are zero
D. Does not exist
Answer : A
15. When a closely coiled helical spring is subjected to a couple about its axis, the stress induced in the wire material of the spring is
A. Bending stress only
B. A combination of torsional shear stress and bending
C. Direct shear stress only
D. A combination of bending stress and direct shear stress
Answer : A
16. A connecting rod is designed as a
A. Long column
B. Short column
C. Strut
D. All of these
Answer : C
17. In order to avoid tearing of the plate at an edge, the distance from the centre line of the rivet hole to the nearest edge of the plate should be equal to (where d = Diameter of rivet hole)
A. d
B. 1.5 d
C. 2.5 d
D. 2 d
Answer : B
18. When two helical springs of equal lengths are arranged to form a cluster spring, then
A. Shear stress in each spring will be equal
B. Load taken by each spring will be half the total load
C. Only A is correct
D. Both A and B is correct
Answer : D
19. If the centre distance of the mating gears having involute teeth is varied within limits, the velocity ratio.
A. Increases
B. Decreases
C. Remains unchanged
D. None of these
Answer : C
20. In order to determine the stresses in a thin cylinder due to an internal pressure, it is assumed that
A. The effect of curvature of the cylinder wall is neglected
B. The tensile stresses are uniformly distributed over the section of the walls
C. The effect of the restraining action of the heads at the end of the pressure vessel is neglected
D. All of the above
Answer : D
21. The notch sensitivity q is expressed in terms of fatigue stress concentration factor Kf and theoretical stress concentration factor Kt as
A. (Kf + 1)/ (Kt + 1)
B. (Kf - 1)/ (Kt - 1)
C. (Kt + 1)/ (Kf + 1)
D. (Kt - 1)/ (Kf - 1)
Answer : B
22. Screws used for power transmission should have
A. Low efficiency
B. High efficiency
C. Very fine threads
D. Strong teeth
Answer : B
23. Surface endurance limit of gear material is dependent upon its
A. Elastic strength
B. Yield strength
C. Brinell hardness number
D. Toughness
Answer : C
24. The coefficient of friction in belt drive depends upon
A. Material of belt
B. Material of pulley
C. Materials of belt and pulley
D. Belt velocity
Answer : C
25. In worm gears, the angle between the tangent to the pitch helix and an element of the cylinder, is known as
A. Helix angle
B. Pressure angle
C. Pitch lead angle
D. None of these
Answer : A
26. Screws used for power transmission should have
A. Very fine threads
B. High efficiency
C. Low efficiency
D. Strong teeth
Answer : B
27. If two springs are in parallel then their overall stiffness will be
A. Half
B. Same
C. Double
D. None of the above
Answer : C
28. Two shafts A and B under pure torsion are of identical length and identical weight and are made of the same material. The shaft A is solid and the shaft B is hollow. We can say that
A. Shaft B is better than shaft A
B. Shaft A is better than shaft B
C. Both the shafts are equally good
D. None of these
Answer : A
29. A connecting rod should be
A. Strong in buckling about X-axis
B. Strong in buckling about Y-axis
C. Equally strong in buckling about X-axis and Y-axis
D. Any one of the above
Answer : C
30. The stress in the threaded part of the bolt will be __________ as compared to the shank.
A. Same
B. Higher
C. Lower
D. None of these
Answer : B
31. When an open coiled helical compression spring is subjected to an axial load (W), the compression produced in the spring will be (where n = No. of active turns of the spring, and G = Modulus of rigidity for the spring material)
A. 2WD3n/Gd?
B. 4WD3n/Gd?
C. 8WD3n/Gd?
D. 16WD3n/Gd?
Answer : C
32. The application of third type levers is found in
A. Handle of a hand pump
B. Hand wheel of a punching press
C. Lever of a loaded safety valve
D. A pair of tongs
Answer : D
33. For applications involving high stresses in one direction only the following type of thread would be best suited
A. ISO metric thread
B. Acme thread
C. Square thread
D. Buttress thread
Answer : D
34. The cold working of metals is carried out __________ the recrystallisation temperature.
A. Above
B. Below
C. At
D. None of these
Answer : B
35. The ratio of endurance limit in shear to the endurance limit in flexure is
A. 0.33
B. 0.4
C. 0.5
D. 0.55
Answer : D
36. In a multiple V-belt drive, when a single belt is damaged, it is preferable to change the complete set in order to
A. Reduce vibration
B. Reduce slip
C. Ensure uniform loading
D. Ensure proper alignment
Answer : C
37. The arms of the pulleys for flat belt drive have
A. Elliptical cross-section
B. Major axis in plane of rotation
C. Major axis twice the minor axis
D. All the three characteristics
Answer : D
38. A key way lowers
A. The strength of the shaft
B. The rigidity of the shaft
C. Both the strength and rigidity of the shaft
D. The ductility of the shaft
Answer : C
39. The value of Lewis form factor used in design of gears is
A. Dependent on number of teeth of a gear
B. Dependent on system of teeth
C. Independent of size of teeth
D. All of these
Answer : D
40. The process extensively used for making bolts and nuts is
A. Hot piercing
B. Extrusion
C. Cold peening
D. Cold heading
Answer : D
41. A bolt of M 24 × 2 means that
A. The pitch of the thread is 24 mm and depth is 2 mm
B. Cross-sectional area of the threads is 24 mm²
C. The nominal diameter of bolt is 24 mm and pitch is 2 mm
D. The effective diameter of bolt is 24 mm and there are 2 threads per cm
Answer : C
42. The centrifugal tension in belts
A. Decreases the power transmitted
B. Increases the power transmitted
C. Increase the wrap angle
D. Increases the belt tension without increasing power transmission
Answer : D
43. The usual clearance provided in hydrodynamic bearing per mm of diameter of shaft is
A. 0.01 micron
B. 0.1 micron
C. 1 micron
D. 10 microns
Answer : C
44. When bevel gears connect two shafts whose axes intersect at an angle greater than a right angle and one of the bevel gears has a pitch angle of 90°, then they are known as
A. Crown bevel gears
B. Angular bevel gears
C. Mitre gears
D. Internal bevel gears
Answer : A
45. Three different weights fall from a certain height under vacuum. They will take
A. Same time to reach earth
B. Times proportional to weight to reach earth
C. Times inversely proportional to weight to reach earth
D. None of the above
Answer : A
46. The ratio of driving tensions in V-belt drives is __________ flat belt drives.
A. Equal to
B. sin? times more than
C. sin? times less than
D. cosec? times more than
Answer : D
47. The form factor of a helical gear __________ with the increase in the helix angle.
A. Increases
B. Decreases
C. Remains constant
D. None of these
Answer : A
48. Two helical springs of the same material and of equal circular crosssection, length and number of turns, but having radii 80 mm and 40 mm, kept concentrically (smaller radius spring within the larger radius spring), are compressed between two parallel planes with a load W. The inner spring will carry a load equal to
A. W/2
B. 2W/3
C. W/9
D. 8W/9
Answer : B
49. A coupling used to connect two perfectly aligned shafts, is
A. Muff coupling
B. Compression coupling
C. Flange coupling
D. All of these
Answer : D
50. The ratio of the ultimate stress to the design stress is known as
A. Elastic limit
B. Strain
C. Factor of safety
D. Bulk modulus
Answer : C

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