# Multiple choice questions (MCQ) on Strength of materials

Multiple choice questions (MCQ) on Strength of materials

1. When a body is subjected to transverse vibration, the stress included in a body will be

a. Shear stress              b. Bending stress

c. Tensile stress            d. None of the above

2. Hooks law holds good up to

a. Yield point                 b. Elastic limit

c. Plastic limit               d. None of the above

3. The change in length due to tensile or compressive force acting on a body is given by

a. PlA/E            b. Pl/AE            c. E/PlA                        d. None of the above

4. Materials which are usually most ductile

a. Face centred cubic lattice                  b. Body centred cubic lattice

c. Hexagonal closed packed lattice        d. None of the above

5. When a body is subjected to three mutually perpendicular stress of equal intensity, the ratio of direct stress to the corresponding volumetric strain is known as

a. Young’s modulus      b. Bulk modulus

c. Modulus of rigidity     d. None of the above

6. The extremities of any diameter on Mohr’s circle represent.

a. Principal stress                                  b. Normal stress on plane at 45 degree

c. Shear stress on plane 45 degree          d. None of the above

7. A body is subjected to a tensile stress of 60 MPa on a plane and another tensile stress of 600 MPa on a plane at right angles to the former. It is also subjected to a shear stress of 400 MPa on the same planes. The maximum normal stress is

a. 400 MPa       b. 500 MPa       c. 1400 MPa      d. None of the above

8. A body is subjected to a two normal 20 MPa (tensile) and 10 MPa (compressive) acting perpendicular to each other. The maximum shear stress is

a. 5 MPa           b. 10 MPa         c. 15 MPa         d. None of the above

9. Young’s modulus is a ratio of

a. Strain/Stress             b. Change in length/Original length

c. Stress/Strain             d. Stress/Original length

10. The ratio of lateral strain to the linear strain is

a. Bulk modulus                        b. Young’s modulus

c. Poisson’s ratio                      d. Modulus of rigidity

11. A simply supported beam of length ‘l’ is subjected to a symmetrical uniformly varying load with zero intensity at the ends and intensity ‘w’ (load per unit length) at the mid span. What is the maximum bending moment?

a. 3wl2/8            b. wl2/12            c. wl2/24            d. 5wl2/12

12. Which one of the following is represented by the area of the S.F. diagram from one end upto a given location on the beam?

a. B.M. at the location               b. Load at the location

c. Slope at the location              d. Deflection at the location

13. For which of the following columns, Euler buckling load = 4П2EI/l2?

a. Column with both hinged ends           b. Column with one end fixed and other end free

c. Column with both ends fixed              d. Column with one end fixed and other hinged

14. A horizontal beam under bending has a maximum bending stress of 100 MPa and a maximum shear stress of 20 MPa. What is the maximum principal stress in the beam?

a. 20                 b. 50                 c. 50+√2900                  d. 100

15. A closed coil helical springs has 15 coils. If five coils of this spring are removed by cutting, the stiffness of the modified spring will

a. increases to 2.5 times                        b. increases to 1.5 times

c. reduce to 0.66 times                          d. remain unaffected

16. Consider the following statement for a simply supported beam subjected to a couple at its mid span.

1. Bending moment is zero at the ends and maximum at the centre

2. Bending moment is constant over the entire length of the beam

3. Shear force is constant over the entire length of the beam

4. Shear force is zero over the entire length of the beam

Which of the following statements given above are correct?

a. 1, 3 and 4                  b. 2, 3 and 4                 c. 1 and 3                     d. 2 and 4

17. Two shafts having the same length and material are joined in series. If the ratio of the diameter of the first shaft to that of the second shaft is 2, then the ratio of the angle of twist of the first shaft to that of the second shaft is

a. 16                 b. 8                  c. 4                   d. 2

18. Which one of the following pairs is not correctly matched?

(a) Slenderness ratio: The ratio of length of the column to the least radius of gyration

(b) Buckling factor: The ratio of maximum load to the permissible axial load on the column

(c) Short column: A column for which slenderness ratio ˂ 32

(d) Strut: A member of a structure in any position and carrying an axial compressive load.

19. The volumetric strain of a thin cylindrical shell with flat ends and subjected to internal pressure is the sum of

a. Longitudinal and hoop stress                              b. Longitudinal and diametrical strain

c. hoop stress and twice the longitudinal strain        d. Longitudinal strain and twice the hoop strain

20. On a plane, resultant stress is inclined at an angle of 45° to the plane. If the normal stress is 100N/mm2, the shear stress on the plane is

a. 71.5 N/mm2               b. 100 N/mm2                c. 86.6 N/mm2               d. 120.8 N/mm2

21. For which one of the following columns, Euler buckling load = (4П2EI)/l2?

a. Column with both ends hinged           b. Column with one end fixed and other end free

c. Column with both ends fixed              d. Column with one end fixed and other hinged.

22. A horizontal beam under bending has a maximum bending stress of 100 MPa and a maximum shear stress of 20 MPa. What is the maximum principal stress in the beam?

a. 20                 b. 50                 c. 50 + √2900                d. 100

23. A closed coil helical spring has 15 coils. If five coils of this spring are removed by cutting, the stiffness of the modified spring will

a. increases to 2.5 times            b. increase to 1.5 times

c. reduce to 0.66 times              d. remain unaffected

24. For σ1 ≠ σ2 and σ3 = 0, what is the physical boundary for Rankine failure theory?

a. A rectangle                b. An ellipse                  c. A square                   d. A parabola

25. The volumetric strain of a thin cylindrical shell with flat ends and subjected to internal pressure is the sum of

a. Longitudinal and hoop strain                                b. Longitudinal and diametrical strain

c. hoop strain and twice the longitudinal strain          d. longitudinal strain and twice the hoop strain

26. A simply supported beam of span l is subjected to a uniformly varying load having zero intensity at the left support and w N/m at the right support. The reaction at the right support is

a. wl/2               b. wl/5              c. wl/4               d. wl/3

27. A cast iron specimen in a torsion test gives a

a. cup and cone fracture                                      b. fracture along a plane normal to the axis of the specimen

c. fracture along a helix of approximately 45°         d. fracture along a plane inclined at 60° to the axis

28. A shaft is subjected to a bending moment M=400 N.m. and Torque T=300 N.m. The equivalent bending moment is

a. 900 N.m                    b. 700 N.m                    c. 500 N.m                    d. 450 N.m

29. The percentage change in volume of a thin cylinder under internal pressure having hoop stress = 200 MPa, E = 200 GPa and Poisson’s ratio = 0.25 is

a. 0.40                          b. 0.30                          c. 0.25                          d. 0.20

30. If the numbers of turns in a spring are halved, its stiffness is

a. halved           b. doubled        c. increased four times              d. not changed