PRINCIPAL STRESSES:

1. The normal stress on an oblique plane at an angle to the cross-section of a body which is

subjected to a direct tensile stress (p) is equal to_________________

2. In question 1, the normal stress on the oblique plane will be maximum when is equal

to______

3. The tangential or shear stress on an oblique plane at an angle to the cross-section of a body

which is subjected to a direct tensile stress (p) is equal to ____

4. In question 3, the tangential stress or shear stress on the oblique plane will be maximum when

is equal to _____

5. The resultant stress on an oblique plane at an angle to the cross-section of a body which is

subjected to a direct tensile stress (p) is equal to ____

6. If a member is subjected to an axial tensile load, the plane normal to the axis of loading carries

a) Minimum normal stress b) maximum normal stress c) ) maximum shear stress d) none of

the above.

7. If a member is subjected to an axial tensile load, the plane inclined at 450 to the axis of loading

carries

a) Minimum normal stress b) maximum normal stress c) ) maximum shear stress d) none of

the above.

8. If a member is subjected to an axial tensile load, then the maximum shear stress induced is

a) Maximum normal stress b) half the maximum normal stress c) twice the maximum normal

stress d) thrice the maximum normal stress

9. If a member, whose tensile strength is more than two times the shear strength is subjected to

an axial load upto failure of the member will occur by

a) Minimum normal stress b) maximum normal stress c) ) maximum shear stress d) none of

the above.

10. Principal plane is a plane on which shear stress is

a) Maximum b) minimum c) average of maximum and minimum d) zero

11. Principal stress are the stresses acting normal to

a) A plane b) an oblique plane c) a principal plane d) a plane having minimum shear stress

12. A member of crosssectional area 10 cm2 is subjected to an axial load od 10,000 N. A plane

makes an angle of 300 to the cross-section. The normal stress on this plane will be ___

13. For the question 12, the shear stress on the 300 plane will be ____

14. If in question 12, the plane makes an angle of 600 instead of 300 to the cross-section, the normal

stress on 600 plane will be

a) Double of 300 plane b) equal to 300 plane c) half of 300 plane d) one-third of 300 plane

15. For the question 14, the shear stress on 600 plane will be

a) Double of 300 plane b) equal to 300 plane c) half of 300 plane d) one-third of 300 plane

16. A body is subjected to two principal stresses p1 and p2 in two mutually perpendicular directions,

the normal stress, on an oblique plane at an angle with the principal plane on which p1 is

acting, is equal to ______

17. For the question 16, the tangential or shear stress on the oblique plane is equal to _____

18. For the question 16, the resultant stress on the oblique plane is equal to _____

19. Choose the wrong statement.

a) To avoid the shear failure of a material (which is subjected to a tensile load) along a plane at

an angle of 450 to the direction of tensile stress, the material should have its shear strength

at least equal to half the tensile strength

b) Key is made weaker link in the design of pulley, key and shaft.

c) The planes, which carry no shear stress, are known as principal stress

d) The normal stress on an oblique plane will be maximum when the angle of oblique plane

with cross-section is 45 degrees

20. A body is subjected to two principal stresses p1 and p2 in two mutually perpendicular directions.

Obliquity is the angle made by

a) Oblique plane with the direction of p1

b) Oblique plane with the direction of p2

c) The line of action of the resultant stress with the normal of the oblique plane

d) The line of action of the resultant stress with the oblique plane

21. The obliquity () is expressed mathematically as _____

22. Two principal tensile stresses of magnitudes 400 N/cm2 and 200 N/cm2 are acting at a point

across two perpendicular planes. An oblique plane makes an angle of 300 with the major

principal plane. The normal stress on the oblique plane will be ____

23. In question 22, the tangential stress along the oblique plane will be ___

24. In question 22, the resultant stress acting on the oblique plane is _____

25. The obliquity in question 22 is equal to _____

26. Choose the wrong statement.

a) The resultant of the two equal and like principal stresses, on any plane is equal to either of

the principal stresses.

b) The resultant of the two equal and like principal stresses, on any plane is normal to the

plane.

c) The resultant of the two equal and unlike principal stresses, on any plane is equal to either

of the principal stresses.

d) The resultant of the two equal and unlike principal stresses, on any plane is normal to the

plane

27. Two unequal like principal stresses are acting at a point across two perpendicular directions. An

oblique plane makes an angle with the major principal plane. As the angle increases,

obliquity () ______ a) increases b) decreases c) first increases then decreases d) remains

consant.

28. In question 27, the maximum obliquity () is given by

a) = tan-1

b) = tan-1

c) = Sin-1

d) = Sin-1

29.