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

1. When a circular beam of diameter d is subjected to a shear force F, the maximum shear stress induced will be
A. 4F/ ?d²
B. 6F/ ?d²
C. 8F/ ?d²
D. 16F/ 3?d²
Answer : D

2. In Vickers hardness testing, the pyramid indentor apex is
A. 40°
B. 122°
C. 136°
D. 152°
Answer : C

3. In the levers of first type, the mechanical advantage is __________ one.
A. Less than
B. Equal to
C. More than
D. None of these
Answer : C

4. Which of the following pipe joints would be suitable for pipes carrying steam?
A. Flanged
B. Threaded
C. Bell and spigot
D. Expansion
Answer : D

5. 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

6. Surface endurance limit of gear material is dependent upon its
A. Elastic strength
B. Yield strength
C. Brinell hardness number
D. Toughness
Answer : C

7. 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

8. The load cup of a screw jack is made separate from the head of the spindle to
A. Prevent the rotation of load being lifted
B. Enhance the load carrying capacity of the jack
C. Reduce the effort needed for lifting the working load
D. Reduce the value of frictional torque
Answer : A

9. The included angle for the V-belt is usually
A. 10°-20°
B. 30°-40°
C. 40°-60°
D. 60°-80°
Answer : B

10. The static tooth load should be __________ the dynamic load.
A. Equal to
B. Less than
C. Greater than
D. None of these
Answer : C

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

12. 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

13. The velocity factor for precision metallic gears cut with high accuracy and operating at velocities upto 20 m/s is equal to
A. 0.75/ (0.75 + ?v)
B. 3/ (3 + v)
C. 4.5/ (4.5 + v)
D. 6/ (6 + v)
Answer : A

14. For circumferential joint in boilers, the type of joint used is
A. Butt joint with single cover plate
B. Butt joint with double cover plate
C. Lap joint with one ring overlapping the other
D. Any one of the above
Answer : C

15. Soderberg relation is based on __________ of the material whereas all other failure relation for dynamic loading are based on ultimate strength of the material.
A. Elastic strength
B. Yield strength
C. Shear strength
D. None of these
Answer : B

16. 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

17. According to I.B.R., the efficiency of a double riveted butt joint with double cover straps of equal width should be
A. 45 to 60 %
B. 63 to 70 %
C. 70 to 83 %
D. 80 to 90 %
Answer : C

18. Which of the following statement is correct?
A. The stress concentration in static loading is more serious in ductile materials and less serious in brittle materials
B. The stress concentration in static loading is more serious in brittle materials and less serious in ductile materials
C. The toughness of a material increases when it is heated
D. The shear stress in a beam varies from zero at the neutral surface and maximum at the outer fibres
Answer : B

19. The bending moment M and a torque T is applied on a solid circular shaft. If the maximum bending stress equals to maximum shear stress developed, then M is equal to
A. T/2
B. T
C. 2T
D. 4T
Answer : A

20. A hot short metal is
A. Brittle when cold
B. Brittle when hot
C. Brittle under all conditions
D. Ductile at high temperature
Answer : B

21. When carbon in the cast iron is principally in the form of graphite, the cast iron will be of
A. Brown colour
B. Yellow colour
C. White colour
D. Grey colour
Answer : D

22. The cold working of metals is carried out __________ the recrystallisation temperature.
A. Above
B. Below
C. At
D. None of these
Answer : B

23. A screw is said to be over hauling screw, if the
A. Friction angle is less than helix angle
B. Friction angle is more than helix angle
C. Friction angle is equal to helix angle
D. Efficiency of screw is 100%
Answer : A

24. During hot working of metals,
A. Porosity of the metal is largely eliminated
B. Grain structure of the metal is refined
C. Mechanical properties are improved due of refinement of grains
D. All of the above
Answer : D

25. The plasticity is the property of a material which enables it to
A. Regain its original shape after deformation when the external forces are removed
B. Draw into wires by the application of a tensile force
C. Resist fracture due to high impact loads
D. Retain deformation produced under load permanently
Answer : D

26. If a spring is cut down into two springs, the stiffness of cut springs will be
A. Half
B. Same
C. Double
D. None of the above
Answer : C

27. The gears are termed as medium velocity gears, if their peripheral velocity is
A. 1-3 m/s
B. 3-15 m/s
C. 15-30 m/s
D. 30-50 m/s
Answer : B

28. Plastic flow in ductile materials
A. Increases the seriousness of static loading stress concentration
B. Lessens the seriousness of static loading stress concentration
C. Has no effect on it
D. Depends on other considerations
Answer : B

29. The endurance limit in shear of carbon steel can be obtained by multiplying the endurance limit in flexure by a factor of
A. 0.45
B. 0.55
C. 0.65
D. 0.75
Answer : D

30. An Involute pinion and gear are in mesh. If both have the same size of addendum, then there will be interference between the
A. Tip of the pinion and flank of gear
B. Tip of the gear and flank of pinion
C. Flanks of both gear and pinion
D. Tip of both gear and pinion
Answer : B

31. The building up of worn and undersized parts, subjected to repeated loads by electroplating is
A. Best method
B. Extremely hazardous
C. Has no effect as regards fatigue strength
D. Cheapest method
Answer : A

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

33. The most important dimension in the design of a nut is
A. Pitch diameter
B. Inside diameter
C. Outside diameter
D. Height
Answer : D

34. When the shaft rotates in anticlockwise direction at slow speed in a bearing, it will
A. Have contact at the bottom most of the bearing
B. Move towards right of the bearing making no metal to metal contact
C. Move towards right of the bearing making the metal to metal contact
D. Move towards left of the bearing making metal to metal contact
Answer : D

35. A taper key which fits half in the key way of the hub and half in the key way of shaft, is known as
A. Angular bevel gears
B. Mitre gears
C. Crown Bevel gears
D. Internal bevel gears
Answer : B

36. When the bearing is subjected to large fluctuations of load and heavy impacts, the bearing characteristic number should be _________ the bearing modulus.
A. 10 times
B. 5 times
C. 15 times
D. 20 times
Answer : C

37. In standard taper roller bearings, the angle of taper of outer raceway is
A. 5°
B. 8°
C. 15°
D. 25°
Answer : D

38. In unilateral system of tolerance, the tolerance is allowed on
A. Both sides of the actual size
B. One side of the actual size
C. One side of the nominal size
D. Both sides of the nominal size
Answer : C

39. 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

40. Rankine Gordon formula for buckling is valid for
A. Long column
B. Short column
C. Short and long column
D. Very long column
Answer : C

41. 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

42. The difference between the tooth space and the tooth thickness as measured on the pitch circle, is called
A. Working depth
B. Clearance
C. Backlash
D. Face width
Answer : C

43. When compared to the rod of the same diameter and material, a wire rope
A. Is less flexible
B. Has a much smaller load carrying capacity
C. Does not provide much warning before failure
D. Provides much greater time for remedial action before failure
Answer : B

44. Coaxing is the procedure of increasing
A. Metal strength by cycling
B. Metal hardness by surace treatment
C. Metal resistance to corrosion by coating
D. Fatigue limit by overstressing the metal by successively increasing loadings
Answer : D

45. The maximum normal stress theory is used for
A. Plastic materials
B. Brittle materials
C. Non-ferrous materials
D. Ductile materials
Answer : B

46. The process extensively used for making bolts and nuts is
A. Hot piercing
B. Extrusion
C. Cold peening
D. Cold heading
Answer : D

47. Which of the following has threads at both ends?
A. Bolt
B. Tap bolt
C. Stud
D. None of these
Answer : C

48. 18/8 steel contains
A. 18% nickel and 8% chromium
B. 18% chromium and 8% nickel
C. 18% nickel and 8% vanadium
D. 18% vanadium and 8% nickel
Answer : B

49. A tapered key which fits in a key way in the hub and the bottom of which is shaped to fit the curved surface of the shaft, is known as,
A. Hollow saddle key
B. Hollow key
C. Soft key
D. None of these
Answer : A

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