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.

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.

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

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

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

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

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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