Question

On a principal plane, the relationship between the stress components is such that

• A. The normal stress is maximum and shear stress is maximum
• B. The normal stress is zero and shear stress is maximum
• C. The shear stress is zero and normal stress is an extremum
• D. The normal stress and shear stress are equal in magnitude

Hint:

On principal planes, \[ \boxed{ \tau=0 } \] and \[ \boxed{ \sigma=\sigma_1\ \text{or}\ \sigma_2. } \]

Answer 1

The Correct Option is C

Step 1: Recall the definition of a principal plane. A principal plane is the plane on which the shear stress becomes zero. \[ \boxed{ \tau=0. } \]

Step 2: Determine the normal stress. On the principal plane, the normal stress attains either its maximum or minimum value. Thus, \[ \boxed{ \text{Normal stress is an extremum while shear stress is zero.} } \] Hence, \[ \boxed{(C)} \] is the correct answer.