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# Strength of Materials MCQs Normal & Shear Stress

In the given figure a stepped column carries loads. What will be the maximum normal stress in the column at B in the larger diameter column if the ratio of P/A here is unity?

a) 1/1.5

b) 1

c) 2/1.5

d) 2

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Answer: cExplanation: Normal stress at B = Total load acting at B / Area of a cross-section at B = (P + P) / 1.5 A = 2P/ 1.5A = 2/1.5.

The stress which acts in a direction perpendicular to the area is called ____________

a) Shear stress

b) Normal stress

c) Thermal stress

d) None of the mentioned

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Answer: bExplanation: Normal stress acts in a direction perpendicular to the area. Normal stress is of two types tensile and compressive stress.

Which of these are types of normal stresses?

a) Tensile and compressive stresses

b) Tensile and thermal stresses

c) Shear and bending

d) Compressive and plane stresses

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Answer: aExplanation: The normal stress is divided into tensile stress and compressive stress.

In a body loaded under plane stress conditions, what is the number of independent stress components?

a) 1

b) 2

c) 3

d) 6

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Answer: cExplanation: In a body loaded under plane stress conditions, the number of independent stress components is 3 I.e. two normal components and one shear component.

If a bar of large length when held vertically and subjected to a load at its lower end, its won-weight produces additional stress. The maximum stress will be ____________

a) At the lower cross-section

b) At the built-in upper cross-section

c) At the central cross-section

d) At every point of the bar

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Answer: bExplanation: The stress is the load per unit area. After the addition of weight in the bar due to its loading on the lower end the force will increase in the upper cross-section resulting in the maximum stress at the built-in upper cross-section.

Which type of stress does in a reinforcement bar is taken by the concrete?

a) Tensile stress

b) Compressive stress

c) Shear stress

d) Bending stress

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Answer: bExplanation: Concrete has the property of taking a good amount of compressive stress. So, In the reinforcement bar, the compressive stress is taken by the concrete.

A material has a Poisson’s ratio of 0.5. If uniform pressure of 300GPa is applied to that material, What will be the volumetric strain of it?

a) 0.50

b) 0.20

c) 0.25

d) Zero

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Answer: dExplanation: As volumetric strain = (1-2μ)σ/E Here the value of μ is 0.5 so 1 – 2 * 0.5 becomes zero. Therefore whatever be the stress the value of volumetric strain will be zero.

A diagram which shows the variations of the axial load for all sections of the pan of a beam is called ____________

a) Bending moment diagram

b) Shear force diagram

c) Thrust diagram

d) Stress diagram

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Answer: dExplanation: The stress diagram shows the variation of the axial load for all sections of the pan. The bending moment diagram shows the variation of moment in a beam. The shear force diagram shows the variation in the shear force due to loading in the beam.

The stress induced in a body, when subjected to two equal and opposite forces which are acting tangentially across the resisting section resulting the shearing of the body across its section is called ____________

a) Bending stress

b) Compressive stress

c) Shear strain

d) Shear stress

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Answer: dExplanation: Shear stress makes the body to shear off across the section. It is tangential to the area over which it acts. The corresponding strain is the shear strain.

What is the formula for shear stress?

a) Shear resistance/shear area

b) Force/unit area

c) Bending strain/area

d) Shear stress/length

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Answer: aExplanation: When force is applied, the twisting divides the body. The resistance is known as shear resistance and shear resistance per unit area is known as shear stress.

Which of the following stresses are associated with the tightening of a nut on a bolt? P. Crushing and shear stress in threads Q. Bending stress due to the bending of bolt R. Torsional shear stress due to frictional resistance between the nut and the bolt Select the correct answer using the codes given below:

a) P and Q

b) P and R

c) Only P

d) Only R

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Answer: aExplanation: Bending stress comes when there is some kind of eccentric load. Torsional stress will come when the nut is rotating. Shear stress will come in tightening of a nut on bolt.

The transverse shear stress acting in a beam of rectangular cross-section, subjected to a transverse shear load, is ____________

a) variable with maximum at the bottom of the beam

b) Variable with maximum at the top of the beam

c) Uniform

d) Variable with maximum on the neutral axis

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Answer: dExplanation: Maximum value of shear stress at neutral axis is τ = 3/2 τmean So, transverse shear stress is variable with a maximum in the neutral axis.

A block 100mm x 100mm base and 10mm height. What will the direct shear stress in the element when a tangential force of 10kN is applied to the upper edge to a displacement 1mm relative to lower face?

a) 1Pa

b) 1MPa

c) 10MPa

d) 100Pa

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Answer: bExplanation: Shear stress = 10kN / 100mmx100mm = 1 N/mm2 = 1MPa.

### Strength of Materials MCQs Bending Stress

A beam is said to be of uniform strength, if ____________

a) B.M. is same throughout the beam

b) Shear stress is the same through the beam

c) Deflection is the same throughout the beam

d) Bending stress is the same at every section along its longitudinal axis

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Answer: dExplanation: Beam is said to be uniform strength if at every section along its longitudinal axis, the bending stress is same.

Stress in a beam due to simple bending is ____________

a) Directly proportional

b) Inversely proportional

c) Curvilinearly related

d) None of the mentioned

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Answer: aExplanation: The stress is directly proportional to the load and here the load is in terms of bending. So the stress is directly proportional to bending.

Which stress comes when there is an eccentric load applied?

a) Shear stress

b) Bending stress

c) Tensile stress

d) Thermal stress

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Answer: bExplanation: When there is an eccentric load it means that the load is at some distance from the axis. This causes compression in one side and tension on the other. This causes bending stress.

What is the expression of the bending equation?

a) M/I = σ/y = E/R

b) M/R = σ/y = E/I

c) M/y = σ/R = E/I

d) M/I = σ/R = E/y

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Answer: aExplanation: The bending equation is given by M/I = σ/y = E/R where M is the bending moment I is the moment of inertia y is the distance from neutral axis E is the modulus of elasticity R is the radius.

On bending of a beam, which is the layer which is neither elongated nor shortened?

a) Axis of load

b) Neutral axis

c) Center of gravity

d) None of the mentioned

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Answer: bExplanation: When a beam is in bending the layer in the direction of bending will be In compression and the other will be in tension. One side of the neutral axis will be shortened and the other will be elongated.

The bending stress is ____________

a) Directly proportional to the distance of layer from the neutral layer

b) Inversely proportional to the distance of layer from the neutral layer

c) Directly proportional to the neutral layer

d) Does not depend on the distance of layer from the neutral layer

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Answer: aExplanation: From the bending equation M/I = σ/y = E/R Here stress is directly proportional to the distance of layer from the neutral layer.

Consider a 250mmx15mmx10mm steel bar which is free to expand is heated from 15C to 40C. what will be developed?

a) Compressive stress

b) Tensile stress

c) Shear stress

d) No stress

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Answer: dExplanation: If we resist to expand then only stress will develop. Here the bar is free to expand so there will be no stress.

The safe stress for a hollow steel column which carries an axial load of 2100 kN is 125 MN/m2. if the external diameter of the column is 30cm, what will be the internal diameter?

a) 25 cm

b) 26.19cm

c) 30.14 cm

d) 27.9 cm

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Answer: bExplanation: Area of the cross section of column = π/4 (0.302 – d2) m2 Area = load / stress. So, π/4 ( 0.302 – d2) m2 = 21 / 125 d = 26.19cm.

### Strength of Materials MCQs Tensile Stress

During a tensile test on a ductile material ____________<br />

a) Nominal stress at fracture is higher than the ultimate stress<br />

b) True stress at fracture is higher than the ultimate stress<br />

c) True stress a fracture is the same as the ultimate stress<br />

d) None of the mentioned

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Answer: bExplanation: In a ductile material, the true stress at fracture will be higher the ultimate stress.

When equal and opposite forces applied to a body, tend to elongate it, the stress so produced, is called ____________

a) Shear stress

b) Compressive stress

c) Tensile stress

d) Transverse stress

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Answer: cExplanation: When subjected to two equal and opposite pulls as a result of which there is an increase in length. This produces tensile stress.

Which of the following stresses are associated with the tightening of a nut on a bolt? P. Tensile stress due to the streching of bolt Q. Bending stress due to the bending of bolt R. Torsional shear stress due to frictional resistance between the nut and the bolt Select the correct answer using the codes given below.

a) P and Q

b) P and R

c) Only p

d) R and Q

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Answer: aExplanation: Bending stress comes when there is some kind of eccentric load. When nut is tightened, the bolt will pull itself and stretching will be there resulting in the tensile stress. Torsional stress will come when the nut is rotating.

In a tensile test, near the elastic limit zone ____________

a) Tensile stress increases in linear proportion to the stress

b) Tensile stress increases at a faster rate

c) Tensile stress decreases at a faster rate

d) None of the mentioned

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Answer: cExplanation: The stress first decreases and then decreases before the strain hardening occurs. The decreases in the stress is due to the attraction between carbon molecules.

Match the following and give the correct code given in options:<br />

List 1 | List 2 |
---|---|

A. Tensile test on CI | 1. Plain fracture on a transverse plane |

B. Tensile test on MS | 2. Granular helecoidal fracture |

C. Torsion test on CI | 3. Cup and cone |

4. Granular fracture in a transverse plane |

a) A – 1 B – 2 C – 4<br />

b) A – 1 B – 4 C – 2<br />

c) A – 3 B – 1 C – 2<br />

d) A – 3 B – 4 C – 1

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Answer: dExplanation: Tensile test on CI is done on cup and cone. Torsion test on MS is on plain fracture on a traverse plane.

The phenomenon of slow growth of strain under a steady tensile stress is called ____________

a) Yielding

b) Creeping

c) Breaking

d) None of the mentioned

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Answer: bExplanation: Creeping is the phenomenon of slow growing strain under a stress for a period of time.

A rod 150cm long and of diameter 2cm is subjected to an axial pull of 20kN. What will be the stress?

a) 60 N/mm2

b) 65 N/mm2

c) 63.6 N/mm2

d) 71.2 N/mm2

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Answer: cExplanation: The stress = load / area Load = 20,000N Area = π/4 (20)2 = 100π mm2.

The stress in a rod is 70 N/mm2 and the modulus of elasticity is 2 x 105 N/mm2. what will be the strain in the rod?

a) 0.00052

b) 0.00035

c) 0.00030

d) 0.00047

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Answer: bExplanation: As E = σ/e Here, E = 2 * 105 N/mm2 And, σ = 70 N/mm2 e = 70/2*105 = 0.00035.

What will be the minimum diameter of a steel wire, which is used to raise a load of 4000N if the stress in the rod is not to exceed 95 MN/m2?

a) 6mm

b) 6.4mm

c) 7mm

d) 7.3mm

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Answer: dExplanation: As stress = load / area Area = load/stress Also, area is π/4 D2 so π/4 D2 = 4000 / 95 And D = 7.32.

A tensile test was conducted on mild steel bar. The load at elastic limit was 250kN and the diameter of the steel bar was 3cm. What will be the value of stress?

a) 35368 x 104 N/m2

b) 32463 x 104 N/m2

c) 35625 x 104 N/m2

d) 37562 x 104 N/m2

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Answer: aExplanation: The stress = load / area Load = 150 x 1000N Area = π/4 (0.03)2 m2.