# Stress MCQ – Strength of Materials

1. A metal bar of length 200 m is inserted between 2 rigid supports and its temperature is increased by 30°C. If the coefficient of thermal expansion is 15 × 10-6 per °C and the Young’s modulus is 2 × 105 MPa, then the stress in the
bar is

1. 90,000 MPa
2. 60 MPa
3. 6000 MPa
4. 90 MPa

2. If all the dimensions of a prismatic bar increase in the proportion n : 1, the proportion with which the maximum stress produced in the bar by its own weight will change by

1. 1 : n2
2. 1 : n
3. : 1
4. n : 1

3. A load of 100 kN suddenly acts on a bar of 100 cm2 area of cross-section and of length 300 mm. Maximum stress developed in the bar is

1. 10 MPa
2. 20 MPa
3. 30 MPa
4. 40 MPa

4. A rod 20 mm x 20 mm cross-section is carrying an axial tensile load 40 kN.what is the value of tensile stress developed in this rod?

1. 100MPa
2. 10 MPa
3. 1 MPa
4. 1000 MPa

5. A tube of aluminium of 40 mm external diameter and 20 mm internal diameter is snugly fitted on a solid steel rod of 20 mm diameter. The composite bar is subjected to an axial compressive force P. If the stress on steel bar is 70 N/mm2, the stress in the aluminium tube and corresponding value of P will be: (E for steel: 2 × 105 N/mm2 and E for aluminium: 7 × 104 N/mm2)

1. 24.5 N/mm2, 45.08 kN
2. 36.5 N/mm2, 60.10 kN
3. 54.5 N/mm2, 73.10 kN
4. 73.80 N/mm2, 92.60 kN

6. A Steel bar having cross-sectional area of 100π mm2 is subjected to a tensile force of 40 kN. Determine the tensile stress.

1. 127.23 MPa
2. 150 MPa
3. 175.25 MPa
4. 200.05 MPa

7. A square steel rod 20 mm × 20 mm in section is to carry an axial load of 100 kN. Calculate the stress.

1. 1,50,000 kN/m2
2. 2,50,000 kN/m2
3. 4,50,000 kN/m2
4. 3,50,000 kN/m2

1. 5
2. 4
3. 3
4. 2

9. A steel rod of length ‘L’ and diameter ‘d’ fixed at both ends, is uniformly heated to a temperature rise of ΔT. The modulus of elasticity of material is ‘E’ and Thermal expansion coefficient is ‘α’. Thermal stress in rod is

1. EαΔTL
2. αΔT
3. EαΔT
4. zero

10. Type of stress that causes dilation is known as

1. Thermal stress
2. Shear stress
3. Deviatoric stress
4. Hydrostatic stress

11. A steel bar of 5 mm is heated from 15° to 40°C and it is free to expand. The bar will induce

1. No stress
2. Shear stress
3. Tensile stress
4. Compressive stress

12. The stress in a steel bar is given as 25,0000 kN/m2 and length of the bar is 50 m. Calculate the shortening of the bar if E = 2.14 × 108 N/mm2

1. 0.160 mm
2. 0.0584 mm
3. 0.250 mm
4. 0.305 mm

13. A steel bar of 500 mm length is under tensile stress of 100 N/mm2. If the modulus of elasticity is 2 × 1011 N/m2, then the total elongation of the bar will be

1. 2.50 mm
2. 0.25 mm
3. 0.50 mm
4. 5.00 mm

14. A concrete beam is post-tensioned by a cable carrying an initial stress of 1000 N/mm2, the slip of jacking end was observed to be 5 mm, modulus of steel is 210 kN/mm2 and span of beam is 30 m; what is % of loss of stress due to anchorage?

1. 2.5%
2. 3.5%
3. 4.0%
4. 1.5%

15. The rate of increase of stress is large in case of

1. Unbonded beams
2. Bonded beams
3. Anchorage beams
4. Tensioned beams

16. Subjected to axial load, the ductile material fails due to

1. axial stress
2. ductility
3. axial strain
4. shear stress

17. The unit of stress in S.I. unit is

1. Kg/cm2
2. Kg/m2
3. N/m2
4. N/cm2

18. A bar of cross-sectional area 2 cm2 and length 100 cm fixed to rigid supports at both ends at a temperature of 25°C. The bar is subjected to an increase in temperature of 30°C. If the coefficient of linear thermal expansion of the
material is 10 × 10-6 °C and Young’s modulus is 2 × 105 N/mm2, the stress in the bar is

1. 10 N/mm2 comp
2. 20 N/mm2 comp
3. 50 N/mm2 tension
4. 50 N/mm2 comp

19. The stress is ‘S’ when a body is subjected to a gradual load W on it. If the load is applied suddenly, the stress shall be

1. S
2. 2S
3. 4S
4. 1.5S