Machine Design MCQ Solved Paper for SSC JE

1. 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

2. When a helical compression spring is cut into halves, the stiffness of the resulting spring will be
A. Same
B. Double
C. One-half
D. One-fourth
Answer : B

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

4. A bolt is designed on the basis of __________ with a large factor of safety.
A. Direct tensile stress
B. Direct compressive stress
C. Direct bending stress
D. Direct shear stress
Answer : A

5. 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

6. 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

7. The washer is generally specified by its
A. Outer diameter
B. Hole diameter
C. Thickness
D. Mean diameter
Answer : B

8. According to I.B.R., shearing resistance required to shear off the rivet per pitch length (in double shear) is (where n = Number of rivets per pitch length)
A. (?/4) d² × ? × n
B. 1.875 × (?/4) d² × ? × n
C. 2 × (?/4) d² × ? × n
D. 3 × (?/4) d² × ? × n
Answer : B

9. The design of shafts made of brittle materials is based on
A. Guest's theory
B. Rankine's theory
C. St Venant's theory
D. Von Mises theory
Answer : B

10. In designing a connecting rod, it is considered like __________ for buckling about Y-axis.
A. Both ends hinged
B. Both ends fixed
C. One end fixed and the other end hinged
D. One end fixed and the other end free
Answer : B

11. In case of pressure vessels having open ends, the fluid pressure induces
A. Longitudinal stress
B. Circumferential stress
C. Shear stress
D. None of these
Answer : B

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. In a gear, having Involute teeth, the normal to the Involute is a tangent to the
A. Base circle
B. Pitch circle
C. Addendum circle
D. Dedendum circle
Answer : A

14. The width of the pulley should be __________ width of the belt.
A. Equal to
B. Less than
C. Greater than
D. None of these
Answer : C

15. A steel containing upto 0.15% carbon is known as
A. Mild steel
B. Dead mild steel
C. Medium carbon steel
D. High carbon steel
Answer : B

16. For same pulley diameters, center distance, belt speed and belt and pulley materials,
A. Open belt drive transmits more power than crossed belt drive
B. Crossed belt drive transmits more power than open belt drive
C. Open and crossed belt drives transmit same power
D. Power transmission does not depend upon open and crossed types of constructions
Answer : B

17. The shear stress at a point in a shaft subjected to a torque is
A. Directly proportional to the polar moment of inertia and to the distance of the point from the axis
B. Directly proportional to the applied torque and inversely proportional to the polar moment of inertia
C. Directly proportional to the applied torque and the polar moment of inertia
D. Inversely proportional to the applied torque and the polar moment of inertia
Answer : B

18. In a multiple V-belt drive, if one of the belts break, then
A. Only the broken belt is replaced
B. The entire set of belts is replaced
C. The broken belt and the belt on either side of it, is replaced
D. The broken belt need not to be replaced
Answer : B

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

20. 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

21. A connecting rod subjected to an axial load may buckle with
A. X-axis as neutral axis
B. Y-axis as neutral axis
C. X-axis or Y-axis as neutral axis
D. Z-axis
Answer : C

22. The endurance or fatigue limit is defined as the maximum value of the stress which a polished standard specimen can withstand without failure, for infinite number of cycles, when subjected to
A. Static load
B. Dynamic load
C. Static as well as dynamic load
D. Completely reversed load
Answer : D

23. 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

24. The rolling contact bearings are known as
A. Thick lubricated bearings
B. Plastic bearings
C. Antifriction bearings
D. Thin lubricated bearings
Answer : C

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

26. A bolt
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. Is provided with pointed threads
Answer : A

27. In case of thick cylinders, the tangential stress across the thickness of cylinder is
A. Maximum at the outer surface and minimum at the inner surface
B. Maximum at the inner surface and minimum at the outer surface
C. Maximum at the inner surface and zero at the outer surface
D. Maximum at the outer surface and zero at the inner surface
Answer : B

28. The period during which the cam follower remains at rest, when cam moves, is known as
A. Constant period
B. Fixed period
C. Dwell period
D. Idle period
Answer : C

29. In a flange coupling, the bolts are subjected to
A. Tensile stress
B. Compressive stress
C. Shear stress
D. None of these
Answer : C

30. 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. Angular bevel gears
B. Mitre gears
C. Internal bevel gears
D. Crown bevel gears
Answer : D

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 material commonly used for crane hooks is
A. Cast iron
B. Wrought iron
C. Mild steel
D. Aluminium
Answer : B

33. Which of the following property is essential for spring materials?
A. Stiffness
B. Ductility
C. Resilience
D. Plasticity
Answer : C

34. 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

35. The bending stress in a curved beam is
A. Zero at the centroidal axis
B. Zero at the point other than centroidal axis
C. Maximum at the neutral axis
D. None of these
Answer : B

36. 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

37. 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

38. According to Indian standards, total numbers of fundamental deviations are
A. 10
B. 15
C. 20
D. 25
Answer : D

39. Shear stress theory is applicable for
A. Ductile materials
B. Brittle materials
C. Elastic materials
D. All of the above
Answer : A

40. According to I.B.R., when the thickness of the boiler shell (t) is less than 8 mm, then the diameter of the rivet hole (d) is obtained by
A. Equating tearing resistance of the plate to the shearing resistance of the rivets
B. Equating tearing resistance of the plate to the crushing resistance of the rivets
C. Equating shearing resistance to the crushing resistance of the rivets
D. None of the above
Answer : C

41. 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

42. Taper usually provided on cotter is
A. 1 in 5
B. 1 in 10
C. 1 in 24
D. 1 in 40
Answer : C

43. 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

44. Allen bolts are
A. Self locking bolts
B. Designed for shock load
C. Used in aircraft application
D. Provided with hexagonal depression in head
Answer : D

45. The stress which vary from a minimum value to a maximum value of the same nature (i.e. tensile or compressive) is called
A. Repeated stress
B. Yield stress
C. Fluctuating stress
D. Alternating stress
Answer : C

46. Which of the following statement is correct?
A. A parallel sunk key is a taperless key
B. A parallel sunk key may be rectangular or square in cross-section
C. A flat saddle key is a taper key which fits in a key way of the hub and is flat on the shaft
D. All of the above
Answer : D

47. When the length of the journal is equal to the diameter of the journal, then the bearing is said to be a
A. Short bearing
B. Long bearing
C. Medium bearing
D. Square bearing
Answer : D

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. If the centre distance of the mating gears having involute teeth is increased, then the pressure angle
A. Increases
B. Decreases
C. Remains unchanged
D. None of these
Answer : A

50. The temperature required for full annealing in hypereutectoid steel is
A. 50°C above upper critical temperature
B. 50°C below upper critical temperature
C. 50°C above lower critical temperature
D. 50°C below lower critical temperature
Answer : A