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STRENGTH OF MATERIALS OBJECTIVE QUESTION-1



1)   The ratio of stress and strain is known as _____
a. Modulus of elasticity
b. Young's modulus
c. Both a. and b.
d. None of the above


2)   The actual breaking stress in stress-strain diagram is the ratio of ______
a. load at breaking point and original cross-sectional area
b. load at breaking point and reduced cross-sectional area
c. maximum load and original cross-sectional area
d. yield load and original cross-sectional area


3)   A rigid body has Poisson's ratio equal to _____
a. 0
b. 1
c. less than 1
d. greater than one

4)   A rectangular bar has volume of 1.5 x 106 mm3. What is the change in volume, if stresses in x, y and z direction are 100 Mpa, 150 Mpa and 160 Mpa respectively. (Assume K = 2 x 105 N/mm2 & μ = 0.3)
a. 1000 mm3
b. 1230 mm3
c. 1500 mm3
d. 2000 mm3


5)   Two parallel, equal and opposite forces acting tangentially to the surface of the body is called as _____
a. Complementary stress
b. Compressive stress
c. Shear stress
d. Tensile stress


6)   Which stress is induced in a member, when expansion or contraction due to temperature variation is prevented?
a. Compressive stress
b. Tensile stress
c. Thermal stress
d. None of the above

7)   The thermal stress induced in a steel rod is compressive, if temperature _____
a. decreases
b. increases
c. remains constant
d. none of the above

8)   The deformation of a material caused due temperature variation develops ______
a. stress
b. strain
c. both a. and b.
d. none of the above



10)   Force of 100 kN is applied on 900 mm long rod of 20 mm diameter and is simultaneously heated at 70o C. What is the total elongation of the rod? (Assume coefficient of thermal expansion = 10 x 10–6 oC, Young's modulus = 150 Gpa)
a. 2.54 mm
b. 2.00 mm
c. 1.27 mm
d. 0.63 mm


11)   The beam having one end free and one end fixed is called as _______
a. Cantilever beam
b. Continuous beam
c. Overhang beam
d. Simply supported beam


12)   The concavity produced on the beam section about the centre line when downward force acts on it is called as __
a. Hogging or positive bending moment
b. Hogging or negative bending moment
c. Sagging or positive bending moment
d. Sagging or negative bending moment

13)   In axial thrust diagram, at which point bending moment is zero?
a. Point of contra-flexure
b. Point of inflection
c. Both a. and b.
d. None of the above

14)   Uniformly varying load between two sections in shear force diagram is represented by ____
a. cubic curve
b. inclined line
c. horizontal line
d. parabolic curve



15)   In bending moment diagram, if no load acts between two sections, then it is represented by _______
a. horizontal line
b. inclined line
c. vertical line
d. all of the above

16)   What is the S.I. unit of sectional modulus?
a. mm4
b. mm3
c. mm2
d. m

17)   What is the moment of inertia acting on a rectangle of width 15 mm and depth 40 mm about base by using theorem of parallel axes?
a. 320 x 103 mm4
b. 300 x 103 mm4
c. 240 x 103 mm4
d. 80 x 103 mm4

18)   What is the moment of inertia acting on a circle of diameter 50 mm?
a. 122.71 x 103 mm4
b. 306.79 x 103 mm4
c. 567.23 x 103 mm4
d. 800 x 103 mm4

19)   Which of the following relations is used to represent theorem of perpendicular axes?
(H = Vertical axis, I = Moment of inertia and K = Radius of gyration)
a. IPQ = Ixx + AH2
b. IPQ = Ixx + Ak2
c. Izz = Ixx + Iyy
d. Izz + Ixx + Iyy = 0

20)   What is the moment of inertia acting on a semicircle of radius 20 mm about the asymmetrical axes?
a. 125.663 x 103 mm4
b. 17600 mm4
c. 1500 mm4
d. 8800 mm4

21)   The shear stress acting on the neutral axis of a beam is _____
a. maximum
b. minimum
c. zero
d. none of the above

22)   Maximum shear stress in a triangular section ABC of height H and base B occurs at _________
a. H
b. H/2
c. H/3
d. neutral axis

23)   What is the shear stress acting along the neutral axis, over a triangular section?
a. 2.66 (S/bh)
b. 1.5 (S/bh)
c. 0.375 (S/bh)
d. None of the above

24)   The average shear stress in a beam of circular section is _______ times the maximum shear stress.
a. 0.75
b. 1.5
c. 4/3
d. equal

25)   A square object of 4 mm is subjected to a force of 3000 N. What is the maximum allowable shear stress acting on it?
a. 250.14 mm2
b. 281.25 mm2
c. 400.32 mm2
d. 500 mm2

26)   According to I.S. code in actual design, maximum permissible deflection is limited to _______
a. (span / 200)
b. (span / 325)
c. (span / 525)
d. none of the above

27)   In cantilever beam, slope and deflection at free end is _____
a. zero
b. maximum
c. minimum
d. none of the above

28)   Which of the following is an elastic curve equation for shear force?
(EI = flexural rigidity)
a. S = EI (dy/dx)
b. S = EI (d2y /dx2)
c. S = EI (d3y / dx3)
d. S = EI (d4y/ dx4)

29)   Deflection of a simply supported beam when subjected to central point load is given as ________
a. (Wl /16 EI)
b. (Wl2 /16 EI)
c. (Wl3 /48 EI)
d. (5Wl4 / 384EI)

30)   Which of the following statements is/are true for a simply supported beam?
a. Deflection at supports in a simply supported beam is maximum
b. Deflection is maximum at a point where slope is zero
c. Slope is minimum at supports in a simply supported beam
d. All of the above

31)   What is the strain energy caused due to self weight in a cylindrical bar?
a. (W2 L) / (6 AE)
b. (W L) / (8 AE)
c. (τ2/ 2G)V
d. (τ2/ G)V

32)   Stress on an object due to sudden load is _________ the stress induced when the load is applied gradually.
a. equal to
b. half
c. twice
d. thrice

33)   What is the strain energy stored in a simply supported beam due to bending moment?
a. ∫ (M2/EI)
b. ∫ (M2/2EI)
c. ∫ (M/2EI)
d. ∫ (2M/EI)

34)   What is the maximum stress induced in a bar 2500 mm2, when a load of 2000 kN is applied suddenly?
a. 400 N/mm2
b. 800 N/mm2
c. 1600 N/mm2
d. Insufficient data

35)   What is the proof resilience of a square bar of 2500 mm2 and 200 mm long, when a load of 150 kN is induced gradually?
(Take E = 150 x 103 Mpa)
a. 45 J
b. 8 J
c. 5.3 J
d. 6 J

36)   In the relation ( T/J = Gθ/L = τ/ R), the letter G denotes modulus of ______
a. elasticity
b. plasticity
c. rigidity
d. resilience

37)   Which of the following relation represents torsional flexibility?
a. GJ
b. GL
c. GJ / L
d. L / GJ

38)   What is the S.I. unit of torsional rigidity?
a. Nm
b. N.m2
c. Nm/ radian
d. None of the above

39)   What is the shear stress acting on the outer surface of a hollow shaft subjected to a torque of 100 Nm?
(The inner and outer diameter of the shaft is 15 mm and 30 mm respectively.)
a. 50.26 N/mm2
b. 40.24 N/mm2
c. 20.120 N/mm2
d. 8.74 N/mm2

40)   Stress in the cross section of a shaft at the centre ________
a. is zero
b. decreases linearly to the maximum value of at outer surface
c. both a. and b.
d. none of the above

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