Strength of Materials

11. A cast iron T section beam is subjected to pure bending. For maximum compressive stress to be three times the maximum tensile stress, centre of gravity of the section from flange side is

1. h/4
2. h/3
3. h/2
4. 2/3 h

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12. A closely coiled helical spring of radius R, contains n turns and is subjected to an axial load W. If the radius of the coil wire is r and modulus of rigidity of the coil material is C, the deflection of the coil is

1. WR³n/Cr⁴
2. 2WR³n/Cr⁴
3. 3WR³n/Cr⁴
4. 4WR³n/Cr⁴

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13. A closely coiled helical spring of radius R, contains n turns and is subjected to an axial loadW. If the radius of the coil wire is r and modulus of rigidity of the coil material is C, the stress developed in the helical spring is

1. WR/πr ³
2. 2WR/πr ³
3. 2WR/πr ²
4. 4WR/πr ²

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14. A column is said to be of medium size if its slenderness ratio is between

1. 20 and 32
2. 32 and 120
3. 120 and 160
4. 160 and 180

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15. A cylinder is said to be thin if the ratio of its thickness and diameter, is less than

1. 45658
2. 43831
3. 42005
4. 43739

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16. A diagram which shows the variations of the axial load for all sections of the span of a beam, is called

1. Bending moment diagram
2. Shear force diagram
3. Thrust diagram
4. Stress diagram

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17. A flywheel on a motor goes from rest to 1000 rpm in 6 sec. The number of revolutions made is nearly equal to

1. 25
2. 50
3. 100
4. 250

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18. A force acting on a body may

1. Introduce internal stresses
2. Balance the other forces acting on it
3. Retard its motion
4. All of the above

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19. A force is completely defined when we specify

1. Magnitude
2. Direction
3. Point of application
4. All of the above

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20. A framed structure is perfect if it contains members equal to

1. 2n³
2. nl
3. 2nl
4. 3n²

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