29. A material which obeys Hook's law, is subjected to direct stress cso. At its elastic limit, the following statement is true,
A. Strain is equal to ?cro
B.b) Maximum shear stress = ?Go
C. Strain energy =o x volume 2E
D. All the above.

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30. A riaterial may fail if
A. maximum principal stress exceeds the direct stress ao
B. maximum strain exceeds
C. maximum shear stress exceeds ?T
D. all the above.

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31. Maximum strain theory for the failure of a material at the elastic limit, is known as
A. Guest's or Trecas' theory
B. St. Venant's theory
C. Rankine's theory
D. Haig's theory

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32. Maximum shear stress theory for the failure of a material at the elastic limit, is known
A. Guest's or Trecas' theory
B. St. Venant's theory
C. Rankine's theory
D. Haig's theory

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33. Maximum principal stress theory for the failure of a material at elastic point, is known
A. Guest's or Trecas' theory
B. St. Venant's theory
C. Rankine's theory
D. Haig's theory

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34. Total strain energy theory for the failure of a material at elastic limit, is known
A. Guest's or Trecas' theory
B. St. Venant's theory
C. Rankine's theory
D. Haig's theory

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35. Shear strain energy theory for the failure of a material at elastic limit, is due to
A. Rankine
B. Guest or Trecas
C. St. Venant
D. Von Mises,

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