Elements of Machine Design-07

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1   If shaft diameter is 60mm, how many bolts are recommended for rigid flange coupling?
(A)   2
(B)   3
(C)   4
(D)   6

2   Determine the diameter of the bolts used in rigid flange coupling if transmitted torque is 270N-m, pitch circle diameter=125mm and four bolts are emplace in the coupling. Permissible shear stress in the bolts is 70N/mm².
(A)   3.8mm
(B)   3.6mm
(C)   4.4mm
(D)   4mm

3   The hub is treated as a solid shaft while calculating torsional shear stress in the hub.
(A)   TRUE
(B)   FALSE

4   Find the shear stress in a flange at the junction of hub in rigid flanged coupling if torsional moment is 2980N-m and diameter of hub being 125mm. Also the thickness of flange is 25mm.
(A)   6.77N/mm2
(B)   10.24N/mm2
(C)   4.84N/mm2
(D)   4.22N/mm2

5   Which property is not required for shaft materials?
(A)   High shear and tensile strength
(B)   Good machinability
(C)   High fatigue strength
(D)   Good cast ability

6   When a solid shaft is subjected to torsion, the shear stress —– induced in the shaft at its center is
(A)   Minimum
(B)   Zero
(C)   Maximum
(D)   Average

7   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

8   When a shaft is subjected to a twisting moment, every cross section of the shaft will be under
(A)   Tensile stress
(B)   Compressive stress
(C)   Shear stress
(D)   Bending stress

9   The product of the tangential force acting on the shaft and its distance from the axis of the shaft (i.e., the radius of the shaft) is known as
(A)   Bending moment
(B)   Twisting moment
(C)   Torsional rigidity
(D)   Flexural rigidity

10   A sunk key fits in the keyway of the —– only.
(A)   Hub
(B)   Sleeve
(C)   Both hub and sleeve
(D)   Neither hub nor sleeve

11   Hollow saddle key is superior to flat saddle key as far as power transmitting capability is concerned.
(A)   TRUE
(B)   FALSE

12   The main advantage of sunk key is that it is a —– drive.
(A)   Positive
(B)   Negative
(C)   Neutral
(D)   None of the listed

13   Woodruff key permits —– movement b/w shaft and the hub.
(A)   Axial
(C)   Eccentric
(D)   None of the listed

14   Determine the length of Kennedy key required to transmit 1200N-m and allowable shear in the key is 40N/mm². The diameter of shaft and width of key can be taken as 40mm and 10mm respectively.
(A)   49mm
(B)   36mm
(C)   46mm
(D)   53mm

15   A universal coupling 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

16   A flange coupling is used to connect two shafts
(A)   Which are perfectly aligned
(B)   Which are not in exact alignment
(C)   Have lateral misalignment
(D)   Whose axes intersect at a small

17   The taper on key is given on
(A)   Bottom side only
(B)   Top side only
(C)   On both sides
(D)   Any side

18   Which of the following statement is wrong?
(A)   A key is used as a temporary fastening
(B)   A key is subjected to tensile stresses
(C)   A key is always inserted parallel to the axis of the shaft
(D)   A key prevents relative motion between the shaft and boss of the pulley

19   In designing a key, it is assumed that the distribution of forces along the length of the key
(A)   Varies linearly
(B)   Is uniform throughout
(C)   Varies exponentially, being more at the torque-input end
(D)   Varies exponentially, being less at the torque-input end

20   The taper on a rectangular sunk key is
(A)   1 in 16
(B)   1 in 32
(C)   1 in 48
(D)   1 in 100

21   The type of stresses developed in the key is/are
(A)   Shear stress alone
(B)   Bearing stress alone
(C)   Both shear and bearing stresses
(D)   Shearing, bearing and bending stresses

22   A saddle key ———- power through frictional resistance only
(A)   Transmits
(B)   Does not transmit

23   The thickness of key is usually taken equal to one-sixth of diameter of shaft.
(A)   Yes
(B)   No

24   Does a keyway slot in shaft reduce the strength of shaft?
(A)   Yes
(B)   No

25   A tapered key which fits in a key way in the hub and if flat on the shaft, is known as
(A)   Feather key
(C)   Wood ruff key
(D)   Flat saddle key

26   When the pulley or other mating piece is required to slide along the shaft, a ———- sunk key is used.
(A)   Rectangular
(B)   Square
(C)   Parallel

27   —- is used to transmit the torque between the shaft and the adjoining machine part like gear, pulley or sprocket.
(A)   Bearing
(B)   Key
(C)   Power screw
(D)   Any of the above

28   Key used when the key is to be removed frequently.
(A)   Sunk Key
(B)   Feather Key
(C)   Woodruff Key
(D)   Gib Head Key

29   Most common key used for industrial purposes.
(A)   Rectangular key
(B)   Square sunk key
(C)   Round key
(D)   Spline key

30   Best use case for round key
(A)   High power transmission
(B)   Low power transmission
(C)   High load capacity

31   Following are the main types of couplings.
(A)   Rigid
(B)   Flexible
(C)   All of the above
(D)   None of the above

32   Which of the following elements is used to connect two shafts?
(A)   Clutch
(B)   Brakes
(C)   Couplings
(D)   None of the above

33   A muff coupling is.
(A)   Rigid coupling
(B)   Flexible coupling
(C)   Shock absorbing coupling
(D)   None of the above

34   A bushed-pin type flange coupling is used.
(A)   For intersecting shafts
(B)   When the shafts are not in exact alignment
(C)   For small shafts rotating at slow speeds
(D)   For parallel shafts

35   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

36   A flange coupling is used to connect two shafts.
(A)   Which are perfectly aligned
(B)   Which are not in exact alignment
(C)   Have lateral misalignment
(D)   Whose axes intersect at a small angle

37   The sleeve or muff coupling is designed as a.
(A)   Dun cylinder
(B)   Hollow shaft
(C)   Solid shaft
(D)   Thick cylinder

38   A Flange Coupling Is.
(A)   Used for non-collinear shafts
(B)   Used for collinear shafts
(C)   Flexible
(D)   Used only on small shafts rotating at slow speeds

39   Actual stress in the bolts of a flanged coupling of a shaft will be.
(A)   More than the designed strength
(B)   Less than the designed strength
(C)   Neither more nor less than the designed strength
(D)   None

40   The flanges of a flange coupling are coupled together by means of bolts and their number depends upon.
(A)   Length of the shaft
(B)   Material of the shaft
(C)   Diameter of the shaft
(D)   Rotational speed of the shaft

41   Which types of coupling used to connect shafts, whose axis are parallel but not in one line?
(A)   Muff coupling
(B)   Flexible coupling
(C)   Oldham’s coupling
(D)   Flange coupling

42   Universal coupling is used to connect two shafts
(A)   Which are perfectly aligned
(B)   Which are not in exact alignment
(C)   Have lateral misalignment
(D)   Whose axes intersect at a small angle

43   The universal coupling is a type of ————
(A)   Flexible coupling
(B)   Rigid coupling
(C)   Both A and B
(D)   None of the above

44   Which of the following coupling is used to connect two shafts which have both lateral and angular misalignment?
(A)   Bush pin type coupling
(B)   Universal coupling
(C)   Oldham coupling
(D)   All of these

45   Which of the following is rigid coupling?
(A)   Muff coupling
(B)   Split muff coupling
(C)   Flange coupling
(D)   All of the above

46   Which Coupling is modification of Flange coupling?
(A)   Bush Pin type
(B)   Oldham
(C)   Universal
(D)   Muff

47   The Coupling Bolts are known as
(A)   Muff
(B)   Nuts
(C)   Pins
(D)   All of above

48   What are the types of Flange Coupling?
(A)   Protected
(B)   Unprotected
(C)   Marine
(D)   All of the above

49   Which of the following is not type of flexible Coupling?
(A)   Oldham Coupling
(B)   Universal Coupling
(C)   None
(D)   Bushed pin type

50   Which Coupling is simpler in design?
(A)   Muff or Sleeve
(B)   Flange
(C)   Bushed pin type
(D)   All above

51   Muff Coupling consist of a hollow cylinder called as
(A)   Shaft
(B)   Muff
(C)   Sleeve
(D)   Both B and C

52   Magnitude of shear stress induced in a shaft due to applied torque varies from
(A)   Maximum at centre to zero at circumference
(B)   Maximum at centre to minimum (not-zero) at circumference
(C)   Zero at centre to maximum at circumference.
(D)   Minimum (not zero) at centre to maximum at circumference

53   The variation of shear stress in a circular shaft subjected to torsion is
(A)   Linear
(B)   Parabolic
(C)   Hyperbolic
(D)   Uniform

54   The relation governing the torsional torque in circular shafts is
(A)   T/r=τ/l=Gθ/J
(B)   T/J=τ/r=Gθ/l
(C)   T/J=τ/l=Gθ/r
(D)   T/l=τ/r=Gθ/J

55   Torsional rigidity of a shaft is defined as
(A)   G/J
(B)   GJ
(C)   TJ
(D)   T/J

56   Torsional rigidity of a shaft is given by
(A)   Gl/θ
(B)
(C)   Tl/θ
(D)   T/l

57   A solid shaft of same cross sectional area and of same material as that of a hollow shaft can resist
(A)   Less torque
(B)   More torque.
(C)   Equal torque
(D)   Unequal torque

58   Angle of twist of a circular shaft is given by
(A)   GJ/Tl
(B)   Tl/GJ
(C)   TJ/Gl
(D)   TG/Jl

59   Maximum shear stress of a solid shaft is given by
(A)   16T/πd
(B)   16T/πd2
(C)   16T/πd3
(D)   16T/πd4

60   The ratio of maximum bending stress to maximum shear stress on the cross section when a shaft is simultaneously subjected to a torque T and bending moment M,
(A)   T/M
(B)   M/T
(C)   2T/M
(D)   2M/T

61   Maximum shear stress in a hollow shaft subjected to a torsional moment is at the
(A)   Middle of thickness
(B)   At the inner surface of the shaft
(C)   At the outer surface of the shaft.
(D)   At the middle surface of the shaft

62   The ratio of strength of a hollow shaft to that of a solid shaft subjected to torsion if both are of the same material and of the same outer diameters, the inner diameter of hollow shaft being half of the outer diameter is
(A)   15/16
(B)   16/15
(C)   7/8
(D)   8/7

63   Ratio of diameters of two shafts joined in series is 2. If the two shafts have the same Material and the same length the ratio of their angles of twist is
(A)   2
(B)   4
(C)   8
(D)   16

64   Ratio of diameters of two shafts joined in series is 2. If the two shafts have the same material and the same length the ratio of their shear stresses is
(A)   2
(B)   4
(C)   8
(D)   16

65   For two shafts joined in series, the ————— in each shaft is same.
(A)   Shear stress
(B)   Angle of twist
(C)   Torque
(D)   Torsional stress

66   For two shafts joined in parallel, the ————— in each shaft is same.
(A)   Shear stress
(B)   Angle of twist
(C)   Torque
(D)   Torsional stress

67   The shafts are NOT made of
(A)   Mild steel
(B)   Alloy steel
(C)   Copper alloys
(D)   Cast iron

68   The shafts are designed on the basis of
(A)   Strength and rigidity
(B)   Ductility
(C)   Malleability
(D)   Resilience

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