Quiznetik

Structural Mechanics | Set 1

1. What is elasticity?

Correct : A. ability to re-gain It's original size and shape

2. What is modular ratio?

Correct : C. ratio of load acting in each section

3. 3.5 m long bar is under tensile load and due to that increase in length of bar is 1.75 mm then strain =

Correct : C. 0.002

4. The increase in the length of a bar of length 1 m, area 300 mm2, modulus of elasticity 2×10^5 N/mm2 due to a tensile load of 120 KN is .

Correct : B. 2mm

5. Shear stress causes .

Correct : D. None of above

6. which of the following has same unit?

Correct : A. modulus of elasticity, pressure, stress

7. unit of stress is .

Correct : D. a and c both

8. In composite section deformation is same in both materials.

Correct : A. True

9. which of the following is type of stress?

Correct : D. all of the above

10. Strain is defined as the ratio of

Correct : B. change in length to original length

11. Hooke's law holds good up to

Correct : B. limit of proportionality

12. Young's modulus is defined as the ratio of

Correct : A. volumetric stress and volumetric strain

13. The unit of Young's modulus is

Correct : D. kg/cm2

14. Deformation per unit length in the direction of force is known as

Correct : D. linear stress

15. It equal and opposite forces applied to a body tend to elongate it, the stress so produced is called

Correct : C. transverse stress

16. The materials having same elastic properties in all directions are called

Correct : D. elastic materials.

17. Modulus of rigidity is defined as the ratio of

Correct : D. shear stress and shear strain

18. If the radius of wire stretched by a load is doubled, then its Young's modulus will be

Correct : D. remain unaffected

19. The intensity of stress which causes unit strain is called

Correct : C. modulus of rigidity

20. Which of the following has no unit

Correct : C. bulk modulus

21. Euler's formula states that the buckling load P for a column of length l, both ends hinged and whose least moment of inertia and modulus of elasticity of the material of the column are I and E respectively, is given by the relation

Correct : C. P=πEIL2

22. Rankine-Golden formula accounts for direct as well as buckling stress and is applicable to

Correct : D. intermediate columns

23. Maximum deflection of a cantilever due to pure bending moment M at its free end, is

Correct : D. ML2/2EI

24. The ratio of the effective length of a column and minimum radius of gyration of its cross-sectional area, is known

Correct : B. slenderness ratio

25. A long vertical member, subjected to an axial compressive load, is called

Correct : A. a column

26. Columns of given length, cross-section and material have different values of buckling loads for different end conditions. The strongest column is one whose

Correct : D. both the ends are fixed

27. The slenderness ratio of a vertical column of square cross- section of 10 cm side and 500 cm long, is

Correct : C. 173.2

28. The equivalent length of a column fixed at one end and free at the other end, is

Correct : D. 2L

29. The radius of gyration of a squar section is not proportional to

Correct : D. side of squar

30. The length of a column, having a uniform circular cross-section of 7.5 cm diameter and whose ends are hinged, is 5 m. If the value of E for the material is 2100 kN/cm2, the permissible maximum crippling load will be

Correct : D. 288.0 kN

31. A sudden increase or decrease in shear force diagram between any two points indicates that there is

Correct : D. None of these

32. A beam is a structural member which is subjected to

Correct : B. Transverse loads and couples

33. Which of the following are statically determinate beams?

Correct : B. Cantilever, overhanging and simply supported

34. A cantilever is a beam whose

Correct : B. One end is fixed and other end is free

35. In a cantilever carrying a uniformly varying load starting from zero at the free end, the shear force diagram is

Correct : C. Follows a parabolic law

36. In a cantilever carrying a uniformly varying load starting from zero at the free end, the Bending moment diagram is

Correct : D. Follows a cubic law

37. In a simply supported beam, bending moment at the end

Correct : A. Is always zero if it does not carry couple at the end

38. For any part of the beam, between two concentrated load Shear force diagram is a

Correct : A. Horizontal straight line

39. For any part of a beam between two concentrated load, Bending moment diagram is a

Correct : C. Line inclined to x-axis

40. For any part of a beam subjected to uniformly distributed load, Shear force diagram is

Correct : C. Line inclined to x-axis

41. For any part of a beam subjected to uniformly distributed load, bending moment diagram is

Correct : D. Parabola

42. In a simple supported beam having length = l and subjected to a concentrated load (W) at mid-point.

Correct : A. Maximum Bending moment = Wl/4 at the mid-point

43. In a cantilever subjected to a concentrated load (W) at the free end and having length =l, Maximum bending moment is

Correct : B. Wl at the fixed end

44. At a point in a simply supported or overhanging beam where Shear force changes sign and = 0, Bending moment is

Correct : A. Maximum

45. In a cantilever subjected to a combination of concentrated load, uniformly distributed load and uniformly varying load, Maximum bending moment is

Correct : C. At the fixed end

46. Point of contra-flexure is a

Correct : D. Point where Bending moment=0 but also changes sign from positive to negative

47. Point of contra-flexure is also called

Correct : C. Point of inflexion

48. The slope of shear force line at any section of the beam is also called

Correct : B. Rate of loading at that section

49. The direction of shear stress in a loaded beam is

Correct : B. Horizontal as well as vertical

50. Shear stress in the beam acting on the cross section is

Correct : B. Tangential to the cross section

51. Which type of load is applied in tensile testing?

Correct : C. Transverse load

52. Which law is also called as the elasticity law?

Correct : C. Hooke’s law

53. The materials which have the same elastic properties in all directions are called __________

Correct : A. Isotropic

54. The calculation of the moment of the body due to the loadings involve a quantity called ____________

Correct : C. Moment of Inertia

55. Moment of Inertia is the integration of the square of the distance of the centroid and the del area along the whole area of the structure.

Correct : A. True

56. What is parallel axis theorem and to whom it is applied?

Correct : A. Theorem used to add the two mutually perpendicular moment of inertias for areas

57. The parallel axis theorem gives the moment of inertia ______________ to the surface of considerance.

Correct : C. Perpendicular

58. In the calculation of the radius of gyration, we use intensity of loadings. So whenever the distributed loading acts perpendicular to an area its intensity varies __________

Correct : A. Linearly

59. Elongation of a bar of uniform cross section of length „L‟, due to its own weight „W‟ is given by

Correct : C. WL/2E

60. steel bar 10 mm x 10 mm cross section is subjected to an axial tensile load of 20kN. If the length of bar is 1 m and E = 200 GPa, then elongation of the bar is:

Correct : A. 1 mm

61. The modulus of rigidity and poisson‟s ratio of a material are 80 GPa and 0.3 respectively. Its young‟s modulus will be

Correct : D. 104 GPa

62. If the value of poisson‟s ratio is zero

Correct : C. there is no linear strain in the material

63. The ratio between direct stress and volumetric strain is:

Correct : A. Bulk modulus

64. Young‟s modulus of a material which gives 2 kN/mm2 stress at 0.01 strain is

Correct : C. 200 kN/mm2

65. The Young‟s modulus of elasticity of a material is 2.5 times its modulus of rigidity. The Poisson‟s ratio for the material will be

Correct : A. 0.25

66. Consider a 250mmx15mmx10mm steel bar which is free to expand is heated from 150C to 400C. what will be developed?

Correct : D. No stress

67. The safe stress for a hollow steel column which carries an axial load of 2100 kN is 125 MN/m2. if the external diameter of the column is 30cm, what will be the internal diameter?

Correct : B. 26.19cm

68. The percentage reduction in area of a cast iron specimen during tensile test would be of the order of

Correct : D. negligible.

69. In a tensile test, near the elastic limit zone, the

Correct : A. tensile strain increases more quickly

70. The stress necessary to initiate yielding is

Correct : A. considerably greater than that necessary to continue it

71. Rupture stress is

Correct : D. load at breaking point/neck area

72. stress at which extension of material takes place more quickly as compared to increase in load is called

Correct : D. yielding point of the material

73. The energy absorbed in a body, when it is strained within the elastic limits, is known as

Correct : A. strain energy

74. Resilience of a material is considered when it is subjected to

Correct : D. shock loading

75. The maximum strain energy that can be stored in a body is known as

Correct : C. proof resilience

76. The total strain energy stored in a body is termed as

Correct : A. resilience

77. Proof resilience per material is known as

Correct : C. modulus of resilience

78. The stress induced in a body due to suddenly applied load compared to when it is applied gradually is

Correct : C. two times

79. strain energy stored in a body due to suddenly applied load compared to when it is applied gradually is

Correct : C. four times

80. During a tensile test on a specimen of 1 cm cross-section, maximum load observed was 8 tonnes and area of cross-section at neck was 0.5 cm2. Ultimate tensile strength of specimen is

Correct : B. 8 tonnes/cm2

81. Tensile strength of a material is obtained by dividing the maximum load during the test by the

Correct : B. original cross-sectional area

82. An axial pull of 50 KN is suddenly applied to a steel bar 2 m long and 1000 mm2 in cross-section. If modulus of elasticity is 200 GPa, find strain energy stored in the bar

Correct : D. 50,000 N.mm

83. A simply supported beam 6 m long and of effective depth 50 cm, carries a uniformly distributed load 2400 kg/m including its self weight. If the lever arm factor is 0.85 and permissible tensile stress of steel is 1400 kg/cm2, the area of steel required, is

Correct : C. 16 cm2

84. A 10 m long mild steel rail section is fixed at 300 K temperature. If temperature increases by 60 K, find stress in rail section if ends are not yielded. Coefficient of thermal expansion is 12×10-6/K.

Correct : B. 144 N/mm2

85. The ultimate shear stress of a mild steel plate of 10 mm thickness is 350 N/mm2. Calculate the diameter of the hole that can be punched to it without exceeding a compressive stress of 700 N/mm2.

Correct : B. 20 mm

86. A bar 2 m long and 20 mm diameter is subjected to an axial pull of 125.6 KN. Due to this load, length increases by 4 mm and diameter reduce by 0.012 mm. Find Poison‟s ratio.

Correct : C. 0.3

87. A composite section of R.C.C. column 300mm×300mm in section having 20mm diameter 4 bars, one at each corner. Strength of concrete is 5 N/mm2 and modular ratio Es/Ec=9. Calculate load taken by column.

Correct : D. 500 KN

88. The moment of inertia of a triangular section of base 3 unit and height 2 unit, about an axis passing through its base is .

Correct : D. 2

89. Moment of inertia of a square of side 1 unit about an axis through its center of gravity, is .

Correct : B. 1/12

90. The axis about which moment of area is taken is known as .

Correct : C. Axis of reference

91. What is the formula of theorem of parallel axis?

Correct : B. Iab = ah2 + Ig

92. Moment of inertia of a circular section of 2 cm diameter, about an axis through its centre of gravity, is .

Correct : B. π/4

93. What is the unit of section modulus?

Correct : C. mm3

94. What is the formula of theorem of perpendicular axis?

Correct : C. Izz – Ixx = Iyy

95. What is the unit of moment of inertia?

Correct : D. mm4

96. What is the unit of Radius of gyration?

Correct : A. mm

97. What is the formula of radius of gyration?

Correct : A. k2 = I/A

98. What will be the radius of gyration of a circular plate of diameter 10cm?

Correct : C. 2.5cm

99. Moment of inertia of any section about an axis passing through its C.G is

Correct : B. Minimum

100. The moment of inertia of a triangular section of base „b‟ and height „h‟ about an axis passing through its base is ……. times the moment of inertia about an axis passing through its C.G. and parallel to the base

Correct : D. 3