**Strength of Materials MCQ**

**SET-3**

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

- A. 23mm
- B. 24.5mm
- C. 25mm
- D. 26mm

**Answer: A**

**62. A beam of uniform strength has**

- A. same cross-section throughout the beam
- B. same bending stress at every section
- C. same bending moment at every section
- D. same shear stress at every section

**Answer: B**

**63. The shear force of a simply supported beam carrying a central point load changes sign at its midpoint**.

- A. Correct
- B. Incorrect

Answer: A

**64. In a simple bending theory, one of the assumption is that the material of the beam is isotropic. This assumption means that the**

- A. normal stress remains constant in all directions
- B. normal stress varies linearly in the material
- C. elastic constants are same in all the directions
- D. elastic constants varies linearly in the material

**Answer: C**

**65. The polar modulus for a solid shaft of diameter (D) is**

**Answer: B**

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

- A. 23mm
- B. 24.5mm
- C. 25mm
- D. 26mm

**Answer: A**

**67. A beam of uniform strength has**

- A. same cross-section throughout the beam
- B. same bending stress at every section
- C. same bending moment at every section
- D. same shear stress at every section

**Answer: B**

**68. The shear force of a simply supported beam carrying a central point load changes sign at its midpoint.**

- A. Correct
- B. Incorrect

**Answer: A**

**69. In a simple bending theory, one of the assumption is that the material of the beam is isotropic. This assumption means that the**

- A. normal stress remains constant in all directions
- B. normal stress varies linearly in the material
- C. elastic constants are same in all the directions
- D. elastic constants varies linearly in the material

**Answer: C**

**70. The polar modulus for a solid shaft of diameter (D) is**

**Answer: B**

**71. The extremeties of any diameter on Mohr’s circle represent**

- A. principal stresses
- B. normal stresses on planes at 45°
- C. shear stresses on planes at 45°
- D. normal and shear stresses on a plane

**Answer: B**

**72. The polar moment of inertia of a hollow shaft of outer diameter (D) and inner diameter (d) is**

**Answer: C**

**73. Two shafts ‘A’ and ‘B’ are made of same material. The shaft ‘A’ is solid and has diameter D. The shaft ‘B’ is hollow with outer diameter D and inner diameter D/2. The strength of hollow shaft in torsion is __________ as that of solid shaft.**

- A. 1/16
- B. 1/8
- C. 1/4
- D. 15/16

**Answer: D**

**74. The bending moment of a cantilever beam of length l and carrying a gradually varying load from zero at free end and w per unit length at the fixed end is __________ at the fixed end.**

- A. wl/2
- B. wl
- C. wl2/2
- D. wl2/6

**Answer: D**

**75. In the below figure, the stress corresponding to point D is**

- A. yield point stress
- B. breaking stress
- C. ultimate stress
- D. elastic limit

**Answer: C**

**76.The Poisson’s ratio for cast iron 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: B**

**77. 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**

**78. 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**

**79. An overhanging beam must overhang on both sides.**

- A. Correct
- B. Incorrect

**Answer: A**

**80. The resultant stress on an inclined plane which is inclined at an angle θ to the normal cross-section of a body which is subjected to a direct tensile stress (σ) in one plane, is**

- A. σ sin θ
- B. σ cos θ
- C. σ sin 2θ
- D. σ cos 2θ

**Answer: B**