Machine Design MCQ Solved Paper for GATE

1. A key made from a cylindrical disc having segmental cross-section, is known as
A. Woodruff key
B. Feather key
C. Flat saddle key
D. Gib head key
Answer : A

2. In skew bevel gearing, the axes of shafts are
A. Intersecting and the teeth are curved
B. Non-intersecting and nonparallel and the teeth are curved
C. Non-intersecting and non-parallel and the teeth are straight
D. None of the above
Answer : C

3. The temperature at which the new grains are formed in the metal is known as
A. Lower critical temperature
B. Upper critical temperature
C. Recrystallisation temperature
D. None of these
Answer : C

4. The face of the tooth is the
A. Surface of the top of the tooth
B. Surface of the tooth above the pitch surface
C. Surface of the tooth below the pitch surface
D. Width of the tooth measured along the pitch circle
Answer : B

5. In hydrostatic bearings
A. The Oil film pressure is generated only by the rotation of the journal
B. The oil film is maintained by supplying oil under pressure
C. Do not require external supply of lubricant
D. Grease is used for lubrication
Answer : B

6. The shock resistance of steel is increased by adding
A. Nickel
B. Chromium
C. Nickel and chromium
D. Cobalt and molybdenum
Answer : C

7. The pitch diameter is the __________ diameter of an external or internal screw thread.
A. Effective
B. Smallest
C. Largest
D. None of these
Answer : A

8. The fatigue stress concentration factor is defined as
A. The ratio of endurance limit with stress concentration to the endurance limit without stress concentration
B. The ratio of endurance limit without stress concentration to the endurance limit with stress concentration
C. The product of the endurance limits with and without stress concentration
D. All of the above
Answer : B

9. In V-belt drive, belt touches
A. At bottom
B. At sides only
C. Both at bottom and sides
D. Could touch anywhere
Answer : B

10. Cast iron pipes are mainly used
A. For conveying steam
B. In water and sewage systems
C. In pressure lubrication systems on prime movers
D. All of the above
Answer : B

11. In a journal bearing, the load on the bearing is __________ to the axis of the journal.
A. Parallel
B. Perpendicular
C. Both A and B
D. None of these
Answer : B

12. The groove angle of pulleys for V-belt is
A. 340 to 360
B. 420 to 450
C. More than 400
D. 300 to 320
Answer : A

13. 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

14. Which is correct statement? Stress concentration in cyclic loading is
A. Very serious in brittle materials and less serious in ductile materials
B. Very serious in ductile materials and less serious in brittle materials
C. Equally serious in both types of materials
D. Seriousness would depend on other factors
Answer : C

15. Lewis form factor for 14 ½° composite and full depth involute system is (where T = Number of teeth)
A. 0.124 - (0.684/T)
B. 0.154 - (0.912/T)
C. 0.175 - (0.841/T)
D. None of these
Answer : A

16. Which of the following coupling is used to connect two shafts which have both lateral and angular misalignment?
A. Bushed pin type coupling
B. Universal coupling
C. Oldham coupling
D. All of these
Answer : D

17. Auto frettage is the method of
A. Joining thick cylinders
B. Calculating stresses in thick cylinders
C. Pre-stressing thick cylinders
D. Increasing the life of thick cylinders
Answer : C

18. In replacing the V-belts, a complete set of new belts is used instead of replacing a single damaged belt because
A. Belts are available in sets
B. Only one belt cannot be fitted with other used belts
C. The new belt will carry more than its share and result in short life
D. New and old belts will cause vibrations
Answer : C

19. Which is positive drive?
A. Flat belt drive
B. V-belt drive
C. Crossed belt drive
D. Timing belt
Answer : D

20. In a flat belt drive, if the slip between the driver and belt is 1 %, between the belt and follower is 3% and driver and follower pulley diameters are equal, then velocity ratio of the drive will be
A. 0.96
B. 0.97
C. 0.98
D. 0.99
Answer : A

21. A spring is used to
A. Measure forces
B. Apply forces C. Store energy
D. All of these
Answer : D

22. The strength of a riveted joint is equal to
A. Tearing strength of plate (P_t)
B. Shearing strength of rivet (P_s)
C. Crushing strength of rivet (P_c)
D. Least value of P_t P_s and P_c
Answer : D

23. Stress concentration is caused due to
A. Variations in load acting on a member
B. Variations in properties of materials in a member
C. Abrupt change of cross-section
D. All of these
Answer : C

24. For a shaft diameter of 200 mm, the number of bolts in a marine flange coupling should be
A. 8
B. 6
C. 4
D. 10
Answer : A

25. The resilience of a bolt may be increased by
A. Increasing its shank diameter
B. Increasing its length
C. Decreasing its shank diameter
D. Decreasing its length
Answer : B

26. A sliding bearing which can support steady loads without any relative motion between the journal and the bearing, is called
A. Hydrostatic lubricated bearing
B. Hydrodynamic lubricated bearing
C. Boundary lubricated bearing
D. Zero film bearing
Answer : A

27. The velocity of sliding ________ the distance of the point of contact from the pitch point.
A. Is directly proportional to
B. Is inversely proportional to
C. Is equal to cos ? multiplied by
D. Does not depend upon
Answer : A

28. 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
Answer : B

29. If T is the actual number of teeth on a helical gear and ? is the helix angle for the teeth, then formative number of teeth is written as
A. T sec³?
B. T sec²?
C. T/sec³?
D. T cosec?
Answer : A

30. When a nut is tightened by placing a washer below it, the bolt will be subjected to following type of loads
A. Compression
B. Tension
C. Shear
D. Combined loads
Answer : B

31. The edges of a boiler plate are bevelled to an angle of
A. 30°
B. 45°
C. 60°
D. 80°
Answer : D

32. In composite or reverse laid ropes
A. Direction of twist of wires in strands is opposite to the direction of twist of strands
B. Direction of twist of wires and strands are same
C. Wires in two adjacent strands are twisted in opposite direction
D. Wires are not twisted
Answer : C

33. The efficiency of a square threaded screw is maximum if the helix angle is equal to (Where ? = Angle of friction)
A. 90° - ?
B. 45° - ?
C. 45° - ?/2
D. 45° + ?/2
Answer : C

34. The velocity factor for very accurately cut and ground metallic gears operating at velocities upto __________ are equal to 6/(6 + v).
A. 10 m/s
B. 12.5 m/s
C. 15 m/s
D. 20 m/s
Answer : D

35. The resistance to fatigue of a material is measured by
A. Elastic limit
B. Ultimate tensile strength
C. Young's modulus
D. Endurance limit
Answer : D

36. When two springs are in series (having stiffness K), the equivalent stiffness will be
A. K
B. K/2
C. 2K
D. K/4
Answer : B

37. In a hydrodynamic lubricated bearing
A. There is a thick film of lubricant between the journal and the bearing
B. There is a thin film of lubricant between the journal and the bearing
C. The lubricant is forced between the journal and the bearing, by external pressure
D. There is no lubricant between the journal and the bearing
Answer : A

38. In thrust bearings, the load acts
A. Along the axis of rotation
B. Parallel to the axis of rotation
C. Perpendicular to the axis of rotation
D. In any direction
Answer : A

39. 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

40. The speed of the sprocket reduces as the chain pitch __________ for a given number of teeth.
A. Increases
B. Decreases
C. Remain same
D. None of these
Answer : A

41. Elastic nut is a locking device in which
A. One small nut is tightened over main nut and main nut tightened against smaller one by loosening, creating friction jamming
B. A slot is cut partly in middle of nut and then slot reduced by tightening a screw
C. Hard fibre or nylon cotter is recessed in the nut and becomes threaded as the nut is stewed on the bolt causing a tight grip
D. Through slots are made at top and a cotter pin is passed through these and a hole in the bolt, and cotter pin splitted and bent in reverse direction at other end
Answer : C

42. According to Indian standards, the diameter of rivet hole is made larger than the basic size of rivet by
A. 0.5 mm upto rivet diameter of 24 mm
B. 1 mm for rivet diameter from 27 mm to 36 mm
C. 2 mm for rivet diameter from 39 mm to 48 mm
D. All of the above
Answer : C

43. The material generally used for aircraft components is
A. Mild steel
B. High speed steel
C. Stainless steel
D. Aluminium
Answer : D

44. A chain drive transmits __________ power as compared to belt drive.
A. More
B. Less
C. Same
D. None of these
Answer : A

45. In radial cams, the follower moves
A. In a direction parallel to the cam axis
B. In a direction perpendicular to the cam axis
C. In any direction irrespective of cam axis
D. Along the cam axis
Answer : B

46. The edges of the plates for cylindrical vessels are usually bevelled to an angle of 80° for
A. Reducing stress concentration
B. Ease of manufacture
C. Safety
D. Fullering and caulking
Answer : D

47. A universal coupling is used to connect two shafts
A. Which are not in exact alignment
B. Which are perfectly aligned
C. Whose axes intersect at a small angle
D. Have lateral misalignment
Answer : C

48. Endurance limit or fatigue limit is the maximum stress that a member can withstand for an infinite number of load applications without failure when subjected to
A. Dynamic loading
B. Static loading
C. Combined static and dynamic loading
D. Completely reversed loading
Answer : D

49. The rated life of a bearing varies
A. Directly as load
B. Inversely as square of load
C. Inversely as cube of load
D. Inversely as fourth power of load
Answer : C

50. In levers, leverage is the ratio of
A. Load lifted to the effort applied
B. Mechanical advantage to the velocity ratio
C. Load arm to the effort arm
D. Effort arm to the load arm
Answer : D