Civil Engineering - Strength of Materials MCQs Part 1

1. A rectangular bar of width b and height h is being used as a cantilever. The loading is in a plane parallel to the side b. The section modulus is

A.

B.

C.

D.
none of these.

 Answer Option C

2. As compared to uniaxial tension or compression, the strain energy stored in bending is only

A.

B.

C.

D.

 Answer Option C

3. The ratio of strengths of solid to hollow shafts, both having outside diameter D and hollow having inside diameter D/2, in torsion, is

A.
1/4

B.
1/2

C.
1/16

D.
15/16

E.
3/8

 Answer Option D

4. The weakest section of a diamond riveting, is the section which passes through

A.
first row

B.
second row

C.
central raw

D.
one rivet hole of end row.

 Answer Option A

5. In a loaded beam, the point of con-traflexture occurs at a section where

A.
bending moment is minimum

B.
bending moment is zero or changes sign

C.
bending moment is maximum

D.
shearing force is maximum

E.
shearing force is minimum.

 Answer Option B

6. The ratio of elongations of a conical bar due to its own weight and that of a prismatic bar of the same length, is

A.

B.

C.

D.

E.

 Answer Option B

7. A three-hinged arch is said to be :

A. statically determinate structure

B. statically indeterminate structure

C. a bent beam

D. none of these.

 Answer Option A

8. The deflection due to couple M at the free end of a cantilever length L is

A.

B.

C.

D.

 Answer Option C

9. The shape of the bending moment diagram over the length of a beam, having no external load, is always

A. linear

B. parabolic

C. cubical

D. circular.

 Answer Option A

10. Pick up the incorrect statement

A. The cross-sectional area of the welded member is effective

B. A welded joint develops strength of its parent metal

C. Welded joints provide rigidity

D. Welded joints have better finish

E. Welding takes more time than riveting.

 Answer Option E

11. A uniform girder simply supported at its ends is subjected to a uniformly distributed load over its entire length and is propped at the centre so as to neutralise the deflection. The net B.M. at the centre will be

A. WL

B.

C.

D.

E.

 Answer Option D

12. A beam of length L is pinned at both ends and is subjected to a concentrated bending couple of moment M at its centre. The maximum bending moment in the beam is

A. M

B. M/2

C. M/3

D. ML/2

 Answer Option A

13. If two forces acting at a joint are not along the straight line, then for the equilibrium of the joint

A. one of the forces must be zero

B. each force must be zero

C. forces must be equal and of the same sign

D. forces must be equal in magnitude but opposite in sign.

 Answer Option B

14. A closely coiled helical spring of radius R, contains n turns and is subjected to an axial load W. If the radius of the coil wire is r and modulus of rigidity of the coil material is C, the stress developed in the helical spring is

A.

B.

C.

D.

 Answer Option B

15. If the shear force along a section of a beam is zero, the bending moment at the section is

A. zero

B. maximum

C. minimum

D. average of maximum-minimum

E. none of these.

 Answer Option B

16. In the cantilever truss as shown in below figure, the horizontal component of the reaction at A, is

A. 30 tonnes

B. 60 tonnes

C. 90 tonnes

D. 120 tonnes

E. 150 tonnes.

 Answer Option A

17. In case of an eccentric loading on a bracket subjected to moment M, the tangential force developed in any rivet, at right angles to its radius vector r is

A.

B.

C.

D.

 Answer Option A

18. A simply supported beam of span L carries a concentrated load W at its mid-span. The maximum bending moment M is

A.

B.

C.

D.

E.

 Answer Option B

19. The ratio of the maximum deflections of a beam simply supported at its ends with an isolated central load and that of with a uniformly distributed load over its entire length, is

A. 1

B.

C.

D.

E.

 Answer Option C

20. The shape of the bending moment diagram over the length of a beam, carrying a uniformly distributed load is always

A. linear

B. parabolic

C. cubical

D. circular.

 Answer Option B

21. The minimum number of rivets for the connection of a gusset plate, is

A. 1

B. 2

C. 3

D. 4

 Answer Option B

22. A triangular section having base b, height h, is placed with its base horizontal. If the shear stress at a depth y from top is q, the maximum shear stress is

A.

B.

C.

D.

 Answer Option A

23. The slenderness ratio of a vertical column of a square cross-section of 2.5 cm sides and 300 cm length, is

A. 200

B. 240

C. 360

D. 416

E. 500

 Answer Option D

24. If n is the ratio of internal and external diameters of a hollow shaft, the ratio of the weight of the hollow shaft and that of solid shaft of same strength, will be

A.

B.

C.

D.

 Answer Option B

25. A rectangular beam 20 cm wide is subjected to a maximum shearing force of 10, 000 kg, the corresponding maximum shearing stress being 30 kg/cm2. The depth of the beam is

A. 15 cm

B. 20 cm

C. 25 cm

D. 30 cm.

 Answer Option C

26. The maximum twisting moment a shaft can resist, is the product of the permissible shear stress and

A. moment of inertia

B. polar moment of inertia

C. polar modulus

D. modulus of rigidly.

 Answer Option C

27. For a simply supported beam with a central load, the bending moment is

A. least at the centre

B. least at the supports

C. maximum at the supports

D. maximum at the centre.

 Answer Option D

28. For a given material Young's modulus is 200 GN/m2 and modulus of rigidity is 80 GN/m2. The value of Poisson's ratio is

A. 0.15

B. 0.20

C. 0.25

D. 0.30

E. 0.40

 Answer Option C

29. The ratio of the moment of inertia of a circular plate and that of a square plate for equal depth, is

A. less than one

B. equal to one

C. more than one

D. equal to 3π/16

E. none of these.

 Answer Option D

30. The force in member U2L2 of the truss shown in below figure, is

A. 10 T tension

B. 10 T compression

C. zero

D. 15 T compression.

 Answer Option B

31. If a shaft is rotating N revolutions per minute with an applied torque T kg-m, the horse power being transmitted by the shaft, is

A.

B.

C.

D.

E. none of these.

 Answer Option C

32. If the width of a simply supported beam carrying an isolated load at its centre is doubled, the deflection of the beam at the centre is changed by

A. 1/2

B. 1/8

C. 2

D. 8

E. 4

 Answer Option A

33. For a simply supported beam of length L, the bending moment M is described as M = a (x - x3/L2), 0 ≤ x < L; where a is a constant. The shear force will be zero at

A. the supports

B. x = L/2

C. x = L/3

D. x = L/3

 Answer Option C

34. The deflection of any rectangular beam simply supported, is

A. directly proportional to its weight

B. inversely proportional to its width

C. inversely proportional to the cube of its depth

D. directly proportional to the cube of its length

E. none of these.

 Answer Option C

35. If a rectangular beam measuring 10 x 18 x 400 cm carries a unformly distributed load such that the bending stress developed is 100 kg/cm2. The intensity of the load per metre length, is

A. 240 kg

B. 250 kg

C. 260 kg

D. 270 kg

E. 280 kg.

 Answer Option D

36. Influence lines are drawn for structures

A. of any type

B. statically determinate

C. pin-jointed truss

D. none of these.

 Answer Option A

37. A shaft turning 150 r.p.m. is subjected to a torque of 150 kgm. Horse power transmitted by the shaft is

A. π

B. 10 π

C. π2

D. 1/π

 Answer Option B

38. A simply supported beam carrying a uniformly distributed load over its whole span, is propped at the centre of the span so that the beam is held to the level of the end supports. The reaction of the prop will be

A. half the distributed load

B. 3/8th the distributed load

C. 5/8th the distributed load

D. distributed load.

E. none of these.

 Answer Option C

39. The range within which a load can be applied on a rectangular column, to avoid any tensile stress, is

A. one-half of the base

B. one-third of the base

C. one-fourth of the base

D. one-fifth of the base

E. one sixth of the base on either side of centroid.

 Answer Option B

40. In a beam, the neutral plane

A. may be its centre

B. passes through the C.G. of the area of cross-section

C. does not change during deformation

D. none of these.

 Answer Option C

41. When loads are applied proportionately to a frame structure containing its members in one plane, the structure is called

A. grid frame

B. plane frame

C. space frame

D. truss frame.

 Answer Option B

42. The shear stress at any section of a shaft is maximum

A. at the centre of the section

B. at a distance r/2 from the centre

C. at the top of the surface

D. at a distance 3/4 r from the centre

E. none of these.

 Answer Option C

43. The region of the cross-section of a column in which compressive load may be applied without producing any tensile stress, is known as the core of the cross-section. In circular columns the radius of the core, is

A. one-half of the radius

B. one-third of the radius

C. one-quarter of the radius

D. one-fifth of the radius

E. one-sixth of the radius.

 Answer Option C

44. A beam is said to be of uniform strength, if

A. B.M. is same throughout the beam

B. deflection is same throughout the beam

C. bending stress is same throughout the beam

D. shear stress is same throughout the beam

E. none of these.

 Answer Option C

45. In a tension test, the yield stress is 300 kg/cm2, in the octa hedral shear stress at the point is:

A. 100 2 kg/cm2

B. 150 2 kg/cm2

C. 200 2 kg/cm

D. 250 2 kg/cm2.

 Answer Option A

46. The radius of gyration of a rectangular section is not proportional to

A. square root of the moment of inertia

B. square root of the inverse of the area

C. square root of the moment of inertia divided by area of the section

D. none of these.

 Answer Option D

47. A reinforced concrete beam is assumed to be made of

A. homogeneous material

B. heterogeneous material

C. isotropic material

D. none of these.

 Answer Option B

48. If the rivets in adjacent rows are staggered and outermost row has only one rivet, the arrangement of the rivets, is called

A. chain riveting

B. zig-zag riveting

C. diamond riveting

D. none of these.

 Answer Option C

49. The energy stored in a beam of length L subjected to a constant B.M. is

A.

B.

C.

D.

 Answer Option A

50. The force in DB of the truss shown in below figure is

A. 3 W compression

B. W tension

C. 2 W compression

D. 5 W tension

E. 4 W tension.

 Answer Option B