870+ Strength of Materials Solved MCQs

501.

The actual neutral axis of a reinforced cement concrete beam is based on the principle that the moment of areas of compression and tension zones at the neutral axis are equal.

A. Agree
B. Disagree
Answer» A. Agree
502.

Mohr's circle is used to determine the stresses on an oblique section of a body subjected to

A. direct tensile strss in one plane accompanied by a shear stress
B. direct tensile stress in two mutually perpendicular directions
C. direct tensile stress in two mutually perpendicular directions accompanied by a simple shear stress
D. all of the above
Answer» A. direct tensile strss in one plane accompanied by a shear stress
503.

The maximum tangential stress in a thick cylindrical shell is always

A. equal to
B. less than
C. greater than
Answer» C. greater than
504.

When a body is subjected to a direct tensile stress (?) in one plane, the maximum shear stress is

A. equal to
B. one-half
C. two-third
D. twice
Answer» B. one-half
505.

The direct stress, across a principal plane, is known as principal stress.

A. Yes
B. No
Answer» A. Yes
506.

The direct stress induced in a long column is

A. same
B. more
C. less
D. negligible
Answer» D. negligible
507.

When a bar of length l, width b and thickness t is subjected to a push of P, its

A. length, width and thickness increases
B. length, width and thickness decreases
C. length increases, width and thickness decreases
D. length decreases, width and thickness increases
Answer» D. length decreases, width and thickness increases
508.

The thickness of a thin cylindrical shell with hemispherical ends is

A. equal to
B. more than
C. less than
Answer» B. more than
509.

The total strain energy stored in a body is called proof resilience.

A. Agree
B. Disagree
Answer» B. Disagree
510.

When shear force at a point is zero, then bending moment is

A. zero
B. minimum
C. maximum
D. infinity
Answer» C. maximum
511.

For a shaft, the shear stress at a point is

A. equal to
B. directly proportional to
C. inversely proportional to
Answer» B. directly proportional to
512.

The elongation of a conical bar under its own weight is

A. equal to
B. half
C. one-third
D. two-third
Answer» C. one-third
513.

When a body is subjected to a direct tensile stress (?), maximum normal stress is equal to the direct tensile stress.

A. Agree
B. Disagree
Answer» A. Agree
514.

The hoop stress in a thin cylindrical shell is

A. longitudinal stress
B. compressive stress
C. radial stress
D. circumferential tensile stress
Answer» D. circumferential tensile stress
515.

The bending moment at the free end of a cantilever beam is

A. zero
B. minimum
C. maximum
Answer» A. zero
516.

Modular ratio of the two materials is the ratio of

A. linear stress to linear strain
B. shear stress to shear strain
C. their modulus of elasticities
D. their modulus of rigidities
Answer» C. their modulus of elasticities
517.

A beam of uniform strength may be obtained by

A. keeping the width uniform and varying the depth
B. keeping the depth uniform and varying the width
C. varying the width and depth both
D. any one of the above
Answer» D. any one of the above
518.

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

A. same
B. One-half
C. One-fourth
D. One-eighth
Answer» B. One-half
519.

A column with maximum equivalent length has

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» D. one end fixed and the other end free
520.

Two shafts 'A' and 'B' are made of same material. The shaft 'A' is of diameter D and shaft 'B' is of diameter D / 2. The strength of shaft 'B' is

A. one-eight
B. one-fourth
C. one-half
D. four times
Answer» A. one-eight
521.

The distance between the centre of a rivet hole to the nearest edge of plate, is called

A. margin
B. pitch
C. back pitch
D. diagonal pitch
Answer» A. margin
522.

The strain energy stored in a spring, when subjected to maximum load, without suffering permanent distortion, is known as

A. impact energy
B. proof resilience
C. proof stress
D. modulus of resilience
Answer» B. proof resilience
523.

The section modulus of a circular section about an axis through its C.G., is

A. ?d2 / 4
B. ?d2 / 16
C. ?d3 / 16
D. ?d3 / 32
Answer» D. ?d3 / 32
524.

The shear force at a point on a beam is the algebraic

A. sum
B. difference
Answer» A. sum
525.

In case of an under-reinforced beam, the depth of actual neutral axis is

A. same as
B. less than
C. greater than
Answer» B. less than
526.

Rivets are generally specified by

A. thickness of plates to be joined
B. overall length
C. shank diameter
D. diameter of head
Answer» C. shank diameter
527.

Two closely coiled helical springs 'A' and 'B' are equal in all respects but the diameter of wire of spring 'A' is double that of spring 'B'. The stiffness of spring 'B' will be

A. one-sixteenth
B. one-eighth
C. one-fourth
D. one-half
Answer» A. one-sixteenth
528.

The value of equivalent length is taken to be half of the actual length of a column with one end fixed and the other end free.

A. Agree
B. Disagree
Answer» B. Disagree
529.

Two closely coiled helical springs 'A' and 'B' are equal in all respects but the number of turns of spring 'A' is double that of spring 'B'. The stiffness of spring 'A' will be

A. one-sixteenth
B. one-eighth
C. one-fourth
D. one-half
Answer» D. one-half
530.

The neutral axis of a transverse section of a beam passes through the centre of gravity of the section and is

A. in the vertical plane
B. in the horizontal plane
C. in the same plane in which the beam bends
D. at right angle to the plane in which the beam bends
Answer» D. at right angle to the plane in which the beam bends
531.

For a 25 mm hole drilled in plates, the diameter of rivet shank should be

A. 23 mm
B. 24.5 mm
C. 25 mm
D. 26 mm
Answer» A. 23 mm
532.

The maximum bending moment for a simply supported beam with a gradually varying load from zero at both ends and w per metre at the centre, lies at the centre of a beam.

A. Agree
B. Disagree
Answer» A. Agree
533.

The moment of resistance of a balanced reinforced concrete beam is based on the stresses in

A. steel only
B. concrete only
C. steel and concrete both
D. none of these
Answer» C. steel and concrete both
534.

The shear stress at the centre of a circular shaft under torsion is

A. zero
B. minimum
C. maximum
D. infinity
Answer» A. zero
535.

Which of the following statement is correct?

A. The stress is the pressure per unit area.
B. The strain is expressed in mm.
C. Hook's law holds good upto the breaking point
D. Stress is directly proportional to strain within elastic limit.
Answer» D. Stress is directly proportional to strain within elastic limit.
536.

The thermal stress in a bar is

A. directly
B. indirectly
Answer» A. directly
537.

The Poisson's ratio for steel varies from

A. 0.23 to 0.27
B. 0.25 to 0.33
C. 0.31 to 0.34
D. 0.32 to 0.42
Answer» A. 0.23 to 0.27
538.

A steel bar of 5 mm is heated from 15?C to 40?C and it is free to expand. The bar will induce

A. no stress
B. shear stress
C. tensile stress
D. compressive stress
Answer» A. no stress
539.

The tensile strength of ductile materials is

A. equal to
B. less than
C. greater than
Answer» C. greater than
540.

Which of the following statement is correct?

A. The energy stored in a body, when strained within elastic limit is known as strain energy.
B. The maximum strain energy which can be stored in a body is termed as proof resilience.
C. The proof resilience per unit volume of a material is known as modulus of resilience.
D. all of the above
Answer» D. all of the above
541.

When a load on the free end of a cantilever beam is increased, failure will occur

A. at the free end
B. at the fixed end
C. in the middle of the beam
D. at a distance 21 / 3 from free end
Answer» B. at the fixed end
542.

The torsional regidity of a shaft is expressed by the torque required to produce a twist of one radian per unit length of a shaft.

A. True
B. False
Answer» A. True
543.

In a beam subjected to pure bending, the intensity of stress in any fibre is

A. equal to
B. less than
C. more than
D. directly proportional to
Answer» D. directly proportional to
544.

The assumption made in Euler's column theory is that

A. the failure of column occurs due to buckling alone
B. the length of column is very large as compared to its cross-sectional dimensions
C. the column material obeys Hooke's law
D. all of the above
Answer» D. all of the above
545.

Strain rosetters are used tc

A. measure shear strain
B. measure linear strain
C. measure volumetric strain
D. relieve strain
Answer» B. measure linear strain
546.

The bending moment at the centre of a simply supported beam with a gradually varying load from zero at both ends to w per metre at the centre is wl / 4.

A. Yes
B. No
Answer» B. No
547.

In a simple bending theory, one of the assumption is that the plane sections before bending remain plane after bending. This assumption means that.

A. stress is uniform throughout the beam
B. strain is uniform throughout the beam
C. stress is proportional to the distance from the neutral axis
D. strain is proportional to the distance from the neutral axis
Answer» D. strain is proportional to the distance from the neutral axis
548.

Poisson's ratio is the ratio of linear strain to the volumetric strain.

A. True
B. False
Answer» B. False
549.

The assumption, generally, made in the theory of simple bending is that

A. the beam material is perfectly homogenous and isotropic
B. the beam material is stressed within its elastic limit
C. the plane sections before bending remain plane after bending
D. all of the above
Answer» D. all of the above
550.

A closely coiled helical spring is of mean diameter (D) and spring wire diameter (d). The spring index is the ratio of

A. 1 / d
B. 1 / D
C. D / d
D. d / D
Answer» C. D / d
551.

When a body is subjected to a direct tensile stress (?) in one plane, then maximum normal stress occurs at a section inclined at

A. 0?
B. 30?
C. 45?
D. 90?
Answer» A. 0?
552.

The object of caulking in a riveted joint is to make the joint

A. free from corrosion
B. stronger in tension
C. free from stresses
D. leak-proof
Answer» D. leak-proof
553.

The tensile test is carried on

A. ductile
B. brittle
C. malleable
D. plastic
Answer» A. ductile
554.

The critical neutral axis of a reinforced cement concrete beam is based on the principle that the neutral axis is situated at the centre of gravity of a given section.

A. True
B. False
Answer» A. True
555.

Transverse fillet welds are designed for

A. tensile strength
B. compressive strength
C. shear strength
D. bending strength
Answer» A. tensile strength
556.

Lame's theory is associated with

A. thin cylindrical shells
B. thick cylindrical shells
C. direct and bending stresses
D. none of these
Answer» B. thick cylindrical shells
557.

Two solid shafts 'A' and 'B' are made of the same material. The shaft 'A' is of 50 mm diameter and shaft 'B' is of 100 mm diameter. The strength of shaft 'B' is

A. one-half
B. double
C. four times
D. eight times
Answer» D. eight times
558.

The bending moment in the centre of a simply supported beam carrying a uniformly distributed load of w per unit length is

A. zero
B. wl2 / 2
C. wl2 / 4
D. wl2 / 8
Answer» D. wl2 / 8
559.

When a body is subjected to a direct tensile stress (?) in one plane, then normal stress on an oblique section of the body inclined at an angle ? to the normal of the section is

A. ? cos ?
B. ? cos2 ?
C. ? sin ?
D. ? sin2 ?
Answer» B. ? cos2 ?
560.

Two bars of different materials and same size are subjected to the same tensile force. If the bars have unit elongation in the ratio of 2 : 5, then the ratio of modulus of elasticity of the two materials will be

A. 2 ; 5
B. 5 ; 2
C. 4 ; 3
D. 3 ; 4
Answer» B. 5 ; 2
561.

When a shaft is subjected to torsion, the shear stress induced in the shaft varies from

A. manimum at the centre to maximum at the circumference
B. maximum at the centre to minimum at the circumference
C. zero at the centre to maximum at the circumference
D. maximum at the centre of zero at the circumference
Answer» C. zero at the centre to maximum at the circumference
562.

Whenever a material is loaded within elastic limit, stress is

A. equal to
B. directly proportional to
C. inversely proportional to
Answer» B. directly proportional to
563.

A beam supported on more than two supports is called

A. simply supported beam
B. fixed beam
C. overhanging beam
D. continuous beam
Answer» D. continuous beam
564.

A rectangular beam of length l supported at its two ends carries a central point load W. The maximum deflection occurs

A. at the ends
B. at l / 3 from both ends
C. at the centre
D. none of these
Answer» B. at l / 3 from both ends
565.

If the diameter of pressure vessel is 15 times the wall thickness, the vessel is said to be a thick shell.

A. Agree
B. Disagree
Answer» A. Agree
566.

Modulus of resilience is the proof resilience per unit volume of a material.

A. Correct
B. Incorrect
Answer» A. Correct
567.

A column is said to be a short column, when

A. its length is very small
B. its cross-sectional area is small
C. the ratio of its length to the least radius of gyration is less than 80.
D. the ratio of its length to the least radius of gyration is more than 80.
Answer» C. the ratio of its length to the least radius of gyration is less than 80.
568.

If there is a fall in the temperature of a composite body, then a member having greater coefficient of linear expansion will be subjected to compressive stress.

A. True
B. False
Answer» B. False
569.

The Rankine's theory for active earth pressure is based on the assumption that

A. the retained material is homogeneous and cohesionless
B. the frictional resistance between the retaining wall and the retained material is neglected
C. the failure of the retained material takes place along a plane called rupture plane
D. all of the above
Answer» D. all of the above
570.

The vertical column has two moments of inertia (i.e Ixx and Iyy). The column will tend to buckle in the direction of the

A. axis of load
B. perpendicular to the axis of load
C. maximum moment of inertia
D. minimum moment of inertia
Answer» D. minimum moment of inertia
571.

The modulus of elasticity for mild steel is approximately equal to

A. 10 kN/mm2
B. 80 kN/mm2
C. 100 kN/mm2
D. 210 kN/mm2
Answer» D. 210 kN/mm2
572.

Two beams, one of circular cross-section and the other of square cross-section, have equal areas of cross-sections. When these beams are subjected to bending.

A. both beams are equally economical
B. square beam is more economical
C. circular beam is more economical
D. none of these
Answer» B. square beam is more economical
573.

If percentage elongation of a certain specimen made of a material 'A' under tensile test is 30% and the percentage elongation of a specimen with same dimensions made of another material 'B' is 40%, then material 'B' is more ductile than material 'A'.

A. Right
B. Wrong
Answer» A. Right
574.

Principle plane is a plane on which the shear stress is

A. zero
B. minimum
C. maximum
Answer» A. zero
575.

If the slenderness ratio for a column is 100, then it is said to be a

A. long
B. medium
C. short
Answer» A. long
576.

A twisting couple in a shaft induces in the shaft

A. Shear stress
B. Bending moment
C. Deflection
D. All of the above
E. None of the above
Answer» A. Shear stress
577.

The ratio of hoop stress to longitudinal stress for thin spherical shells is

B. 2
C. 0
E. There is no such ratio for spherical shells
Answer» E. There is no such ratio for spherical shells
578.

An unknown weight falls through 1 cm on a collar rigidly attached to the lower end of a vertical bar 3 m long and 6 m2 in section. If the maximum instantaneous extension is 2 mm the value of stress would be

A. 1500 kg/cm2
B. 500 kg/cm2
C. 1000 kg/cm2
D. 1333 kg/cm2
E. 667 kg/cm2
Answer» D. 1333 kg/cm2
579.

The neutral axis of a transverse section of a beam passes through the centre of gravity of the section and is

A. At right angles to the plane in which the beam bends
B. In the same plane in which beam bends
C. In the vertical plane
D. In the horizontal plane
E. None of the above
Answer» A. At right angles to the plane in which the beam bends
580.

The local strain energy at a point in a material when shear stress is 80 MN/m2 and G = 27 GN/m2 will be nearly

A. 58.5 kJ/m3
B. 118.5 kJ/m3
C. 438.5 kJ/m3
D. 2348 kJ/m2
E. None of the above
Answer» B. 118.5 kJ/m3
581.

If shear force is zero along a section, the bending moment at that section will be

A. Minimum
B. Maximum
C. There is no correlation between the two
D. Minimum or Maximum
E. Zero
Answer» D. Minimum or Maximum
582.

The rod of a ceiling fan is subjected to

A. compressive stress
B. tensile stress
C. shear stress
D. torsional stress
E. None of the above
Answer» B. tensile stress
583.

The compression members tend to buckle in the direction of their

A. Axis of load
B. Perpendicular to the axis of load
C. Minimum cross-section
D. Least radius of gyration
E. None of the above
Answer» D. Least radius of gyration
584.

The percentage reduction of area during tensile test on a cast iron specimen may be

A. Negligible
B. 25%
C. 50%
D. 5%
E. 10%
Answer» A. Negligible
585.

The web bukling in beams may be avoided by

A. stiffening the web
B. limiting the stress that can be used
C. increasing the span
D. any of the above methods
E. None of the above
Answer» A. stiffening the web
586.

If the rod in problem 165 stands erected vertically upwards then it will be known as

A. Short column
B. Strut
C. Long column
D. Medium column
E. None of the above
Answer» C. Long column
587.

Which of the following materials can be used for absorption of shock?

A. Rubber
B. Wood
C. sawdust
D. Lead sheet
E. Any of the above
Answer» E. Any of the above
588.

In a compression test the fracture in cast iron specimen would occur along

A. An oblique plane
B. Along the axis of load
C. A light angles to the specimen axis
D. Fracture will not occur in cast iron
E. None of the above
Answer» A. An oblique plane
589.

Shear stresses on mutually perpendicular planes are

A. Equal
B. Maximum
C. Minimum
D. Zero
E. Unequal
Answer» A. Equal
590.

The weakness section of a diamond riveting is the section which passes through

A. End row with one rivet only
B. Row with maximum rivets
C. All rows have same strength
D. The first row
E. Middle row
Answer» A. End row with one rivet only
591.

A 10 mm mild steel rod 40 min long lying on ground will be known as

A. Short column
B. Long column
C. Strut
D. Medium column
E. None of the above
Answer» E. None of the above
592.

Torsional rigidity is

A. The torque that produces rotation of unit r.p.m. in a shaft
B. The torque that transmits one HP at one r.p.m.
C. The torque that produces a twist of one radian in a shaft of unit diameter
D. The torque that produces a twist of one radian in a shaft of unit length
E. None of the above
Answer» D. The torque that produces a twist of one radian in a shaft of unit length
593.

A portion of a beam between two sections is said to be in pure bending when there is

A. constant bending moment and constant shear force
B. constant shear force and zero bending mement
C. constant bending moment and zero shear force
D. zero bending moment and zero shear force
E. None of the above
Answer» C. constant bending moment and zero shear force
594.

A self-supporting steel chimney transmits the lateral forces to the foundation by

A. propped beam action
B. cantilever action
C. simply supported beam action
D. fixed beam action
E. None of the above
Answer» B. cantilever action
595.

The moment of inertia of an area will be least with respect to

A. Vertical axis
B. Moment of area does not depend on axes
C. Moment of area is same through all axes
D. Central axis
E. Horizontal axis
Answer» D. Central axis
596.

A hole, one metre from the end of a structural steel member, is 0.8 mm shy of matching another hole for possible connection. What force, in kN, is necessary to stretch it for connection? The cross section is 25 mm x 3 mm

A. 12.6
B. 13.6
C. 14.7
D. 15.8
E. None of the above
Answer» A. 12.6
597.

Two rods A and B are subjectd to equal load P. Rod A is tapering with bigger diameter D at the support and small end diameter as D/2. Rod B is of uniform cross section with diameter D. The ratio of elongation of rod A to that of B would be

A. 4
B. 2
C. 1
E. None of the above
Answer» B. 2
598.

A beam supporting a uniformly distributed load over its entire length L is pinned at one end and passes over a roller support at a distance x from the other end. The value of x such that the greatest bending moment in the beam is as small as possible, will be

A. 0.111 L
B. 0.2 L
C. 0.125 L
D. 0.33 L
E. 0.293 L
Answer» E. 0.293 L
599.

Hoop stress is

A. Circumferential tensile stress
B. Compressive stress
C. Radial stress
D. Longitudinal stress
E. None of the above
Answer» A. Circumferential tensile stress
600.

A composite spring is made by joining two springs end to end one spring having twice the stiffness of the other. The ratio of the stiffness of the composite spring to that of the stiffness of the two springs could be

A. ?
B. 2
C. 3
D. 3?2
E. ?
Answer» E. ?
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