Strength of Materials - Civil Engineering Questions and Answers
1. Modulus of rigidity is defined as the ratio
of
a) longitudinal stress to longitudinal strain
b) shear stress to shear strain
c) stress to strain
d) stress to volumetric strain
Ans: b
2. If the Young's modulus of elasticity of a
material is twice its modulus of rigidity, then the Poisson's ratio of the
material is
a) -1
b) -0.5
c) 0.5
d) zero
Ans: d
3. Limit of proportionality depends upon
a) area of cross-section
b) type of loading
c) type of material
d) all of the above
Ans: c
4. For an isotropic, homogeneous and elastic
material obeying Hooke's law, number of independent elastic constants is
a) 2
b) 3
c) 9
d) 1
Ans: a
5. In a thin cylindrical shell, the ratio of
longitudinal stress to hoop stress is
a) 0.5
b) 1
c) 2
d) 4
Ans: c
6. If
all the dimensions of a prismatic bar are doubled, then the maximum stress
produced in it under its own weight will
a) decrease
b) remain unchanged
c) increase to two times
d) increase to four times
Ans: c
7. The relationship between Young's, modulus
of elasticity E, bulk modulus K and Poisson's ratio u is given by
a) E = 2K(l-2u.)
b) E = 3K(l + u)
c) E = 3K(l-2u)
d) E = 2K(l + u)
Ans: c
8. Limiting values of Poisson's ratio are
a) - 1 and 0.5
b) -land-0.5
c) 1 and - 0.5
d) 0 and 0.5
Ans: a
9. The elongation of a conical bar under its
own weight is equal to
a) that of a prismatic bar of same length
b) one half that of a prismatic bar of same
length
c) one third that of a prismatic bar of same
length
d) one fourth that of a prismatic bar of same
length
Ans: c
10. If a material has identical properties in
all directions, it is said to be
a) homogeneous
b) isotropic
c) elastic
d) orthotropic
Ans: b
11. Two bars of different materials are of the
same size and are subjected to same tensile forces. If the bars have unit
elongations in the ratio of 4 : 7, then the ratio of moduli of elasticity of
the two materials is
a) 7:4
b) 4:7
c) 4:17
d) 16 :49
Ans: a
12. A prismatic bar of volume V is subjected to
a tensile force in longitudinal direction.
If Poisson's ratio of
the material is u and longitudinal strain is e, then the final volume of the
bar becomes
a) (l + e)(l-u)2V
b) (l-e)2(l + ue)V
c) (l + e)(l-ne)2V
d) (l-ue)3V
Ans: c
13. If a composite bar of steel and copper is
heated, then the copper bar will be under
a) tension
b) compression
c) shear
d) torsion
Ans: b
14. Effective length of a weld is equal to
a) overall length - weld size
b) overall length - throat thickness
c) overall length - 2 x weld size
d) overall length - 2 x throat thickness
Ans: c
15. Size of a right angled fillet weld is given
by
a) 0.707 x throat thickness
b) 0.414 x throat thickness
c) 2.0 x throat thickness
d) throat thickness
Ans: b
16. The effective length of a fillet weld
designed to transmit axial load shall not be less than
a) 2 x size of weld
b) 4 x size of weld
c) 6 x size of weld
d) 10 x size of weld
Ans: b
17. Size of fillet weld with unequal legs is
equal to
a) smaller leg length
b) longer leg length
c) throat thickness
d) average of smaller and longer leg lengths
Ans: a
18. Weakest section in a fillet weld is
a) throat of the fillet
b) smaller side
c) side parallel to force
d) side perpendicular to force
Ans: a
19. Effective throat thickness of a fillet weld
is
a) 0.707 x size of weld
b) 1.414 x size of weld
c) a function of the angle between fusion
faces
d) equal to the side of the fillet
Ans: c
20. According to
Unwin's formula, the dia¬meter of rivet in mm to suit the t mm thickness of
plate is given by
a) 6t
b) 6Vt
c) 1.9-y/t
d) 1.5 t+ 4
Ans: b
21. A flat carrying a
pull of 69C kN is con-nected to a gusset plate using rivets. If the pulls
required to shear the rivet, to crush the rivet and to tear the plate per pitch
length are 68.5 kN, 46 kN and 69 kN respectively, then the number of rivets
required is
a) 10
b) 12
c) 15
d) 20
Ans: c
22. If the rivet value
is 16.8 kN and force in the member is 16.3 kN, then the number of rivets
required for the connection of the member to a gusset plate is
a) 1
b) 2
c) 3
d) 4
Ans: b
23. At a point in a
strained body carrying two unequal unlike principal stresses pi and p2 (Pi >
P2X the maximum shear stress is given by
a) p,/2
b) p2/2
c) (p,-p2)/2
d) (p, + p2)/2
Ans: d
24. If a point in a
strained material is subjected to equal normal and tangential stresses, then
the angle of obliquity is
a) 0°
b) 45°
c) tan"1 (1/2)
d) tan"1 (2)
Ans: b
25. If a prismatic
member with area of cross-section A is subjected to a tensile load P, then the
maximum shear stress and its inclination with the direction of load respectively
are
a) P/A and 45°
b) P/2Aand45°
c) P/2A and 60°
d) P/A and 30°
Ans: b
26. The sum of normal
stresses is
a) constant
b) variable
c) dependent on the planes
d) none of the above
Ans: a
27. The radius of
Mohr's circle for two equal unlike principal stresses of magnitude p is
a) p
b) p/2
c) zero
d) none of the above
Ans: a
28. Shear stress on
principal planes is
a) zero
b) maximum
c) minimum
d) none of the above
Ans: a
29. The state of pure
shear stress is produced by
a) tension in one direction and equal
compression in perpendicular direction
b) equal tension in two directions at right
angles
c) equal compression in two directions at
right angles
d) none of the above
Ans: a
30. According to
Rankine's hypothesis, the criterion of failure of a brittle material is
a) maximum principal stress
b) maximum shear stress
c) maximum strain energy
d) maximum shear strain energy
Ans: a
31. Maximum bending
moment in a beam occurs where
a) deflection is zero
b) shear force is maximum
c) shear force is minimum
d) shear force changes sign
Ans: d
32. Rate of change of
bending moment is equal to
a) shear force
b) deflection
c) slope
d) rate of loading
Ans: d
33. The diagram showing the variation of axial
load along the span is called
a) shear force diagram
b) bending moment diagram
c) thrust diagram
d) influence line diagram
Ans: a
34. The difference in ordinate of the shear
curve between any two sections is equal to the area under
a) load curve between these two sections
b) shear curve between these two sections
c) bending moment curve between these two
sections
d) load curve between these two sections plus
concentrated loads applied between the sections
Ans: d
35. The variation of the bending moment in the
portion of a beam carrying linearly varying load is
a) linear
b) parabolic
c) cubic
d) constant
Ans: c
36. The maximum bending moment due to a moving
load on a fixed ended beam occurs
a) at a support
b) always at the midspan
c) under the load only
d) none of the above
Ans: a
37. A cantilever beam AB of length 1 carries a
concentrated load W at its midspan C. If the free end B is supported on a rigid
prop, then there is a point of contraflexure
a) between A and C
b) between C and B
c) one between A and C and other between C and
B
d) nowhere in the beam
Ans: a
38. A prismatic beam fixed at both ends carries
a uniformly distributed load. The ratio of bending moment at the supports to
the bending moment at mid-span is
a) 0.5
b) 1.0
c) 1.5
d) 2.0
Ans: d
39. A beam of overall length 1 with equal
overhangs on both sides carries a uniformly distributed load over the entire
length. To have numerically equal bending moments at centre of the beam and at
supports, the distance between the supports should be
a) 0.2771
b) 0.403 1
c) 0.5861
d) 0.7071
Ans: c
40. A prismatic beam of length 1 and fixed at
both ends carries a uniformly distributed load. The distance of points of
contraflexure from either end is
a) 0.2071
b) 0.2111
c) 0.2771
d) 0.251
Ans: b
41. A simply supported beam of length 1 carries
a load varying uniformly from zero at left end to maximum at right end. The
maximum bending moment occurs at a distance of
a) 1/V3 from left end
b) 1/3 from left end
c) 1/V3 from right end
d) 1/3 from right end
Ans: a
42. A portion of a beam between two sections is
said to be in pure bending when there is
a) constant bending moment and zero shear
force
b) constant shear force and zero bending
moment
c) constant bending moment and constant shear
force
d) none of the above
Ans: a
43. The ratio of width to depth of a strongest
beam that can be cut out of a cylindrical log of wood is
a) 1/2
b) 1/V2
c) 1/3
d) 2/3
Ans: b
44. Of the several prismatic beams of equal
lengths, the strongest in flexure is the one having maximum
a) moment of inertia
b) section modulus
c) tensile strength
d) area of cross-section
Ans: b
45. Of the two prismatic beams of same
material, length and flexural strength, one is circular and other is square in
cross-section. The ratio of weights of circular and square beams is
a) 1.118
b) 1.342
c) 1.000
d) 0.793
Ans: a
46. A flitched beam consists of a wooden joist
150 mm wide and 300 mm deep strengthened by steel plates 10 mm thick
and 300 mm deep one on
either side of the joist. If modulus of elasticity of steel is 20 times that of
wood, then the width of equivalent wooden section will be
a) 150 mm
b) 350 mm
c) 500 mm
d) 550 mm
Ans: d
47. A beam of
rectangular cross-section is 100 mm wide and 200 mm deep. If the section is
subjected to a shear force of 20 kN, then the maximum shear stress in the
section is
a) 1 N/mm2
b) 1.125 N/mm2
c) 1.33 N/mm2
d) 1.5 N/mm2
Ans: d
48. A beam of square cross-section with side
100 mm is placed with one diagonal vertical. If the shear force
acting on the section is 10 kN, the maximum shear stress is
a) 1 N/mm2
b) 1.125 N/mm2
c) 2 N/mm2
d) 2.25 N/mm2
Ans: b
49. A prismatic bar when subjected to pure
bending assumes the shape of
a) catenary
b) cubic parabola
c) quadratic parabola
d) arc of a circle
Ans: d
50. A beam of triangular cross section is
placed with its base horizontal. The maximum shear stress intensity in the
section will be
a) at the neutral axis
b) at the base
c) above the neutral axis
d) below the neutral axis
Ans: c
51. A beam of uniform strength has at every
cross-section same
a) bending moment
b) bending stress
c) deflection
d) stiffness
Ans: b
52. For no torsion, the plane of bending should
a) be parallel to one of the principal axes
b) pass through shear centre of section
c) pass through neutral axis of the section
d) pass through centre of gravity of the
section
Ans: b
53. Two beams, one of circular cross-section
and other of square cross-section, have equal areas of cross-section. If
subjected to bending
a) circular section is more economical
b) square section is more economical
c) both sections are equally strong
d) both sections are equally stiff
Ans: b
54. 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
a) 0.01 d
b) 0.1 d
c) 0.011 d
d) 0.11 d
Ans: c
55. 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
a) 0 152 1
b) 0.207 1
c) 0.252 1
d) 0.277 1
Ans: a
56. 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
a) deflection at D in
the first case will be equal to the deflection at C in the second case
b) deflection at C in the first case is equal
to the deflection at D in the second case
c) deflection at D in the first case will
always be smaller than the deflection at C in the second case
d) deflection at D in the first case will
always be greater than the deflection at C in the second case
Ans: a
57. 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
a) 0.8 m
b) lm
c) 1.2 m
d) 1.5m
Ans: b
58. If the deflection
at the free end of a uniformly loaded cantilever beam of length 1 m is equal to
7.5 mm, then the slope at the free end is
a) 0.01 radian
b) 0.015 radian
c) 0.02 radian
d) none of the above
Ans: c
58. 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
a) 1/2
b) 3/11
c) 5/24
d) 7/41
Ans: d
59. If the length of a
simply supported beam carrying a concentrated load at the centre is doubled,
the defection at the centre will become
a) two times
b) four times
c) eight times
d) sixteen times
Ans: c
60. 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
a) 50%
b) 25%
c) 12.5%
d) 6.25%
Ans: d
61. A laminated spring is given an initial
curvature because
a) it is more economical
b) it gives uniform strength
c) spring becomes flat when it is subjec-ted
to design load
d) none of the above
Ans: c
62. A laminated spring is supported at
a) ends and loaded at centre
b) centre and loaded at ends
c) ends and loaded anywhere
d) centre and loaded anywhere
Ans: b
63. Laminated springs are subjected to
a) direct stress
b) bending stress
c) shear stress
d) none of the above
Ans: b
64. Deflection in a leaf spring is more if its
a) strength is more
b) strength is less
c) stiffness is less
d) stiffness is more
Ans: c
65. Buckling load for a given column depends
upon
a) length of column only
b) least lateral dimension only
c) both length and least lateral dimension
d) none of the above
Ans: c
66. 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
a) P/16
b) P/4
c) P/2
d) 4P
Ans: a
67. Euler's formula for a mild steel long column
hinged at both ends is not valid for slenderness ratio
a) greater than 80
b) less than 80
c) greater than 180
d) greater than 120
Ans: b
68. A long column has maximum crippling load
when its
a) both ends are hinged
b) both ends are fixed
c) one end is fixed and other end is hinged
d) one end is fixed and other end is free
Ans: b
69. Effective length of a chimney of 20 m
height is taken as
a) 10 m
b) 20m
c) 28.28m
d) 40m
Ans: d
70. Rankine's formula for column is valid when
slenderness ratio
a) lies between 0 and 140
b) lies between 0 and 100
c) is less than 80
d) has any value
Ans: d
71. Slenderness ratio of a 5 m long column
hinged at both ends and having a circular cross-section with diameter 160 mm is
a) 31.25
b) 62.5
c) 100
d) 125
Ans: d
72. The effect of arching a beam is
a) to reduce bending moment throughout
b) to increase bending moment throughout
c) to increase shear force
d) to decrease shear force
Ans: a
73. Internal forces at every cross-section in a
arch are
a) nornal thrust and shear force
b) shear force and bending moment
c) normal thrust and bending moment
d) normal thrust, shear force and bending
moment
Ans: d
74. 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
a) bending moment
b) shear force
c) normal thrust
d) deflection
Ans: a
75. Due to rise in temperature in a three
hinged arch, induced stress is
a) direct compressive
b) direct tensile
c) shear
d) none of the above
Ans: d
76. In a three hinged arch, the linear and the
actual arch meet at
a) at least three points
b) at least two points
c) all points irrespective of loading
d) nowhere
Ans: a
77. If a three hinged parabolic arch carries a
uniformly distributed load over the entire span, then any section of the arch
is subjected to
a) normal thrust only
b) normal thrust and shear force
c) normal thrust and bending moment
d) normal thrust, shear force and bending
moment
Ans: a
78. Three hinged arch is
a) statically indeterminate by one degree
b) statically indeterminate by two degrees
c) statically determinate
d) unstable structure
Ans: c
79. A linear arch has
a) normal thrust only
b) shear force only
c) bending moment only
d) normal thrust and shear force
Ans: a
80. 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
a) circular
b) parabolic
c) elliptical
d) none of the above
Ans: b
81. For a determinate pin-jointed plane frame,
the relation between the number of joints j and members m is given by
a) m = 2j - 3
b) m = 3j-6
c) m > 2j - 3
d) m > 3j - 6
Ans: a
82. The basic perfect frame is a
a) triangle
b) rectangle
c) square
d) hexagon
Ans: a
83. Method of joints is applicable only when
the number of unknown forces at the joint under consideration is not more than
a) one
b) two
c) three
d) four
Ans: b
84. 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
a) 20 mm
b) 31.25 mm
c) 37.5 mm
d) 42.5 mm
Ans: d
85. Proof resilience is the maximum energy
stored at
a) limit of proportionality
b) elastic limit
c) plastic limit
d) none of the above
Ans: b
86. Strain energy stored in a member is given
by
a) 0.5 x stress x volume
b) 0.5 x strain x volume
c) 0.5 x stress x strain x volume
d) 0.5 x stress x strain
Ans: c
87. 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
a) 10 N.m
b) 25 N.m
c) 50 N.m
d) 100N.m
Ans: c
88. 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
a) 50 N/mm2
b) 100 N/mm2
c) 200 N/mm2
d) 400 N/mm2
Ans: c
89. If the depth of a beam of rectangular section
is reduced to half, strain energy stored in the beam becomes
a) 1/4 time
b) 1/8 time
c) 4 times
d) 8 times
Ans: d
90. The specimen in a Charpy impact test
is supported as a
a) cantilever beam
b) simply supported beam
c) fixed beam
d) continuous beam
Ans: b
91. Impact test enables one to estimate
the property of
a) hardness
b) toughness
c) strength
d) creep
Ans: b
92. The phenomenon of decreased resistance of a
material to reversal of stress is called
a) creep
b) fatigue
c) resilience
d) plasticity
Ans:
93. The property of metal which allows it to
deform continuously at slow rate without any further increase in stress is
known as
a) fatigue
b) creep
c) plasticity
d) resilience
Ans: b
94. The stress below which a material has a
high probability of not failing under reversal of stress is known as
a) tolerance limit
b) elastic limit
c) proportional limit
d) endurance limit
Ans: b
95. 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
a) increase definitely
b) decrease definitely
c) be difficult to predict
d) increase or decrease depending upon the
radius of the segmental arch
Ans: b
96. For ductile materials, the most appropriate
failure theory is
a) maximum shear stress theory
b) maximum principal stress theory
c) maximum principal strain theory
d) shear strain energy theory
Ans: a
97. 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
a) 1000 kg/cm2
b) 2000 kg/cm2
c) 2500 kg/cm2
d) 500 kg/cm2
Ans: d
98. For the design of a cast iron member, the
most appropriate theory of failure is
a) Mohr's theory
b) Rankine's theory
c) Maximum strain theory
d) Maximum shear energy theory
Ans: b
About Author:
I am Thomas Britto here to share my experiences in the civil engineering field to all my readers.Today many students are struggling to buy books at high prices. So I decided to start a blog and share my experience and knowledge with all my readers.
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