Quiznetik

Strength of Materials | Set 3

1. The portion, which should be removed from top and bottom of a circular cross section of diameter d in order to obtain maximum section modulus, is

Correct : C. 0.011 d

2. A beam of overall length / rests on two simple supports with equal overhangs on both sides. Two equal loads act at the free ends. If the deflection at the centre of the beam is the same as at either end, then the length of either overhang is

Correct : A. 0 152 1

3. A beam ABC rests on simple supports at A and B with BC as an overhang. D is centre of span AB. If in the first case a concentrated load P acts at C while in the second case load P acts at D, then the

Correct : A. deflection at D in the first case will be equal to the deflection at C in the second case

4. If the deflection at the free end of a uniformly loaded cantilever beam is 15mm and the slope of the deflection curve at the free end is 0.02 radian, then the length of the beam is

Correct : B. lm

5. A cantilever beam carries a uniformly distributed load from fixed end to the centre of the beam in the first case and a uniformly distributed load of same inten¬sity from centre of the beam to the free end in the second case. The ratio of deflections in the two cases is

Correct : D. 7/41

6. If the length of a simply supported beam carrying a concentrated load at the centre is doubled, the defection at the centre will become

Correct : C. eight times

7. A simply supported beam with rectangular cross-section is subjected to a central concentrated load. If the width and depth of the beam are doubled, then the deflection at the centre of the beam will be reduced to

Correct : D. 6.25%

8. A laminated spring is given an initial curvature because

Correct : C. spring becomes flat when it is subjec-ted to design load

9. A laminated spring is supported at

Correct : B. centre and loaded at ends

10. Laminated springs are subjected to

Correct : B. bending stress

11. Deflection in a leaf spring is more if its

Correct : C. stiffness is less

12. Buckling load for a given column depends upon

Correct : C. both length and least lateral dimension

13. When both ends of a column are fixed, the crippling load is P. If one end of the column is made free, the value of crippling load will be changed to

Correct : A. P/16

14. Euler's formula for a mild steel long column hinged at both ends is not valid for slenderness ratio

Correct : B. less than 80

15. A long column has maximum crippling load when its

Correct : B. both ends are fixed

16. Effective length of a chimney of 20 m height is taken as

Correct : D. 40m

17. Rankine's formula for column is valid when slenderness ratio

Correct : D. has any value

18. Slenderness ratio of a 5 m long column hinged at both ends and having a circular crosssection with diameter 160 mm is

Correct : D. 125

19. The effect of arching a beam is

Correct : A. to reduce bending moment throughout

20. Internal forces at every cross-section in a arch are

Correct : D. normal thrust, shear force and bending moment

21. According to Eddy's theorem, the vertical intercept between the linear arch and the centre line of actual arch at any point represents to some scale

Correct : A. bending moment

22. Due to rise in temperature in a three hinged arch, induced stress is

Correct : D. none of the above

23. In a three hinged arch, the linear and the actual arch meet at

Correct : A. at least three points

24. If a three hinged parabolic arch carries a uniformly distributed load over the entire span, then any section of the arch is subjected to

Correct : A. normal thrust only

25. Three hinged arch is

Correct : C. statically determinate

26. A linear arch has

Correct : A. normal thrust only

27. A three hinged arch is carrying uniformly distributed load over the entire span. The arch is free from shear force and bending moment if its shape is

Correct : B. parabolic

28. For a determinate pin-jointed plane frame, the relation between the number of joints j and members m is given by

Correct : A. m = 2j - 3

29. The basic perfect frame is a

Correct : A. triangle

30. Method of joints is applicable only when the number of unknown forces at the joint under consideration is not more than

Correct : B. two

31. A short column of external diameter of 250 mm and internal diameter of 150 mm carries an eccentric load of 1000 kN. The greatest eccentricity which the load can have without producing tension anywhere is

Correct : D. 42.5 mm

32. Proof resilience is the maximum energy stored at

Correct : B. elastic limit

33. Strain energy stored in a member is given by

Correct : C. 0.5 x stress x strain x volume

34. A rectangular block of size 200 mm x 100 mm x 50 mm is subjected to a shear stress of 100 N/mm2. If modulus of rigidity of material is 1 x 105 N/mm2, strain energy stored will be

Correct : C. 50 N.m

35. A steel rod of cross sectional area equal to 1000 mm2 is 5 m long. If a pull of 100 kN is suddenly applied to it, then the maximum stress intensity will be

Correct : C. 200 N/mm2

36. If the depth of a beam of rectangular section is reduced to half, strain energy stored in the beam becomes

Correct : D. 8 times

37. The specimen in a Charpy impact test is supported as a

Correct : B. simply supported beam

38. Impact test enables one to estimate the property of

Correct : B. toughness

39. A fletched beam is used to

Correct : C. Equalize the strength in tension and compression

40. The property of metal which allows it to deform continuously at slow rate without any further increase in stress is known as

Correct : B. creep

41. The stress below which a material has a high probability of not failing under reversal of stress is known as

Correct : B. elastic limit

42. A three hinged parabolic arch rib is acted upon by a single load at the left quarter point. If the central rise is increased and the shape of arch altered to segmental without changing the other details, the horizontal thrust will

Correct : B. decrease definitely

43. For ductile materials, the most appropriate failure theory is

Correct : A. maximum shear stress theory

44. At a point in a steel member, the major principal stress is 2000 kg/cm2 and the minor principal stress is compressive. If the uni-axial tensile yield stress is 2500 kg/cm2, then the magnitude of the minor principal stress at which yielding will commence, according to the maximum shearing stress theory, is

Correct : D. 500 kg/cm2

45. For the design of a cast iron member, the most appropriate theory of failure is

Correct : B. Rankine's theory

46. In a riveted joint, when the rivets in the various rows are opposite to each other, the joint is said to be

Correct : A. chain riveted

47. Two shafts 'A' and 'B' have the same material. The shaft 'A' is solid of diameter 100 mm. The shaft 'B' is hollow with outer diameter 100 mm and inner diameter 50 mm. The torque transmitted by shaft 'B' is

Correct : D. 15 ? 16

48. The ratio of change in volume to the original volume is called

Correct : C. volumetric strain

49. The ratio of bulk modulus to Young's modulus for a Poisson's ratio of 0.25 will be

Correct : B. 2 ? 3

50. If the section modulus of a beam is increased, the bending stress in the beam will

Correct : C. decrease

51. A body is subjected to two normal stresses 20 kN / m2 (tensile) and 10 kN / m2 (compressive) acting perpendicular to each other. The maximum shear stress is

Correct : C. 15 kN / m2

52. In order to avoid sliding of masonry dam, the force of friction between the dam and soil should be at least

Correct : B. 1.5 times

53. In a beam of uniform strength, the bending stress developed is constant and is equal to the allowable stress at every section of the beam.

Correct : A. True

54. The rectrangular beam 'A' has length l, width b and depth d. Another beam 'B' has the same length and depth but width is double that of 'A'. The elastic strength of beam B will be

Correct : B. double

55. A rod is enclosed centrally in a tube and the assembly is lightened by rigid washers. If the assembly is subjected to a compressive load, then

Correct : C. both rod and tube are under compression

56. The shear force in the centre of a simply supported beam carrying a uniformly distributed load of w per unit length, is

Correct : A. zero

57. A beam of triangular section is placed with its base horizontal. The maximum shear stress occurs at

Correct : B. mid of the height

58. The stress developed in the material without any permanent set is called

Correct : A. elastic limit

59. The ductility of a material

Correct : A. increases

60. The rectrangular beam 'A' has length l, width b and depth d. Another beam 'B' has the same length and width but depth is double that of 'A'. The elastic strength of beam B will be

Correct : C. four times

61. A bar of length L metres extends by l mm under a tensile force of P. The strain produced in the bar is

Correct : D. 0.001 l / L

62. In the Euler's formula, the value of C for a column with one end fixed and the other end free, is

Correct : D. 4

63. The maximum stress produced in a bar of tapering section is at

Correct : A. smaller end

64. In a thin cylindrical shell subjected to an internal pressure p, the ratio of longitudinal stress to the hoop stress is

Correct : A. 1 ? 2

65. When two shafts of same length, one of which is hollow, transmit equal torques and have equal maximum stress, then they should have equal

Correct : B. polar modulus

66. In a simple bending theory, one of the assumption is that the material of the beam is isotropic. This assumption means that the

Correct : C. elastic constants are same in all the directions

67. For the two shafts connected in parallel and sub-jected to twisting moment, the angle of twist of each shaft will be same.

Correct : A. Yes

68. A tensile test is performed on a round bar. After fracture it has been found that the diameter remains approximately same at fracture. The material under test was

Correct : B. cast iron

69. The compressive strength of brittle materials is

Correct : C. greater than

70. Two shafts 'A' and 'B' transmit the same power. The speed of shaft 'A' is 250 r.p.m. and that of shaft 'B' is 300 r.p.m. The shaft 'B' has the greater diameter.

Correct : B. False

71. A welded joint as compared to a riveted joint has

Correct : C. more

72. The shear force of a cantilever beam of length l carrying a uniformly distributed load of w per unit length is

Correct : A. zero

73. The bending moment at a point on a beam is the algebraic

Correct : A. sum

74. In the Euler's formula, the value of C for a column with one end fixed and the other end hinged, is 1 / 2.

Correct : A. True

75. The bending moment diagram for a simply supported beam carrying a uniformly distributed load of w per unit length, will be

Correct : D. a parabolic curve

76. Every direct stress is always accompanied by a strain in its own direction and an opposite kind of strain in every direction, at right angles to it. Such a strain is known as

Correct : B. lateral strain

77. The bending stress in a beam is

Correct : D. directly proportional to

78. The section nodulus (Z) of a beam is given by

Correct : A. I / y

79. According to Euler's column theory, the crippling load for a column of length (l) with one end fixed and the other end free is

Correct : B. less than

80. A shear stress across a plane, is always accompanied by a balancing shear stress across the plane and normal to it.

Correct : B. False

81. Two closely coiled helical springs 'A' and 'B' are equal in all respects but the number of turns of spring 'A' is half that of spring 'B'. The ratio of deflections in spring 'A' to spring 'B' is

Correct : C. 1 ? 2

82. A lap joint is always in

Correct : A. single

83. The shear force and bending moment zre zero at the free end of a cantilever beam, if it carries a

Correct : C. uniformly distributed load over the whole length

84. In a thick cylindrical shell subjected to an internal pressure (p), the radial stress across the thickness of a cylinder is

Correct : D. maximum at the inner surface and zero at the outer surface

85. The forsional rigidity of a shaft is given by

Correct : B. T / ?

86. In a tensile test, when the material is stressed beyond elastic limit, the tensile strain

Correct : D. increases more quickly

87. Within elastic limit, shear stress is

Correct : C. directly proportional to

88. A cantilever beam of length / carries a gradually varying load from zero at free end and w per unit length at the fixed end. The maximum deflection oes at

Correct : A. free end

89. The ratio of maximum shear stress developed in a rectangular beam and a circular beam of the same cross-sectional area is

Correct : D. 9 ? 8

90. The rivets are used for

Correct : A. permanent

91. The maximum deflection of a fixed beam carrying a central point load lies at

Correct : B. centre of beam

92. Hook's law holds good up to

Correct : B. elastic limit

93. At the neutral axis of a beam, the shear stress is

Correct : C. maximum

94. The bending moment on a section is maximum where shear force is

Correct : C. changing sign

95. In a thick cylindrical shell subjected to an internal pressure (p), the tangential stress across the thickness of a cylinder is

Correct : B. maximum at the inner surface and minimum at the outer surface

96. The shear modulus of most materials with respect to the modulus of elasticity is

Correct : B. less than half

97. The maximum shear stress developed in a beam of rectangular section is

Correct : C. 1.5 times

98. The maximum shear stress of a beam of triangular section occurs above the neutral axis.

Correct : A. Correct

99. Which of the following is a proper sequence?

Correct : A. proportional limit, elastic limit, yielding, failure

100. Parallel fillet welds are designed for bending strength.

Correct : A. Agree