Stresses In Members(Mechanics Of Materials ) Questions and answers for exam Preparation

Question 1. Match the following and give the correct code given in options:

A – 1 B – 2 C – 4
A – 1 B – 4 C – 2
A – 3 B – 1 C – 2
A – 3 B – 4 C – 1

Explanation:-

Answer: Option D. -> A – 3 B – 4 C – 1
Answer: (d).A – 3 B – 4 C – 1

Question 2. An axial pull of 1kN is acting on a bar of consisting two equal lengths as shown but of dia 10cm and 20cm respectively. What will be the stresses in the two sections respectively in N/mm² ?

0.127 and 0.0031
0.034 and 0.0045
0.153 and 0.003
0.124 and 0.124

Explanation:-

Answer: Option A. -> 0.127 and 0.0031
Answer: (a).0.127 and 0.0031

Question 3. An axial pull of 35000 N is acting on a bar consisting of two lengths as shown with their respective dimensions. What will be the stresses in the two sections respectively in N/mm² ?

111.408 and 49.5146
111.408 and 17.85
97.465 and 49.5146
97.465 and 34.263

Explanation:-

Answer: Option A. -> 111.408 and 49.5146
Answer: (a).111.408 and 49.5146

Question 4. An axial pull of 35000 N on a bar consisting of two lengths as shown with their respective dimensions. What will be the total extension of the bar if the young’s modulus = 2.1 x 10⁵ ?

0.153mm
0.183mm
0.197mm
0.188mm

Explanation:-

Answer: Option B. -> 0.183mm
Answer: (b).0.183mm

Question 5. An axial pull of 20 kN on a bar of two equal lengths of 20cm as shown with their respective dimensions. What will be the total extension of the bar if the young’s modulus = 2×10⁵ ?

0.200mm
0.345mm
0.509mm
0.486mm

Explanation:-

Answer: Option C. -> 0.509mm
Answer: (c).0.509mm

Question 6. An axial residual compressive stress due to a manufacturing process is present on the outer surface of a rotating shaft subjected to bending. Under a given bending load, the fatigue of the shaft in the presence of the residual compressive stress is ____________

Decreased
Increases or decreased, depending on the external bending load
Neither decreased nor increased
Increases

Explanation:-

Answer: Option D. -> Increases
Answer: (d).Increases

Question 7. The length, Young’s modulus and coefficient of thermal expansion of bar P are twice that of bar Q. what will be the ration of stress developed in bar P to that in bar Q if the temperature of both bars is increased by the same amount?

2
8
4
16

Explanation:-

Answer: Option C. -> 4
Answer: (c).4

Question 8. A cube having each side of length p, is constrained in all directions and is heated unigormly so that the temperature is raised to T.C. What will be the stress developed in the cube?

δET / γ
δTE / (1 – 2γ)
δTE / 2 γ
δTE / (1 + 2γ)

Explanation:-

Answer: Option B. -> δTE / (1 – 2γ)
Answer: (b).δTE / (1 – 2γ)

Question 9. A steel bar of 40mm x 40mm square cross-section is subjected to an axial compressive load of 200kN. If the length of the bar is 2m and E=200GPa, the elongation of the bar well be ____________

1.25mm
2.70mm
4.05mm
5.40mm

Explanation:-

Answer: Option A. -> 1.25mm
Answer: (a).1.25mm

Question 10. A steel bar 600mm long and having 30mm diameter, is turned down to 25mm diameter for one fourth of its length. It is heated at 30 C above room temperature, clamped at both ends and then allowed to cool to room temperature. If the distance between the clamps is unchanged, the maximum stress in the bar ( α = 12.5 x 10⁻⁶ per C and E = 200 GN/m²) is

25 MN/m²
40 MN/m²
50 MN/m²
75 MN/m²

Explanation:-

Answer: Option D. -> 75 MN/m²
Answer: (d).75 MN/m²