Question

Which of the following statements are correct for stresses acting on mutually perpendicular faces of a plane element?
1. The sum of the normal stresses in mutually perpendicular planes is equal to the sum of the principal stresses.
2. The shearing stresses in two mutually perpendicular planes are equal in magnitude and direction.
3. Maximum shear stress is half of the difference between principal stresses.

• A. 1, 2 and 3
• B. 1 and 2 only
• C. 2 and 3 only
• D. 1 and 3 only

Answer 1

The correct option is D 1 and 3 only

• The sum of normal stress on mutually perpendicular planes on any oblique plane remains constant.
• The shearing stress on two mutually perpendicular plane is same magnitude but opposite in sense of rotation.
• Maximum shear stress, ${\tau }_{max}=\frac{{\sigma }_1-{\sigma }_2}{2}$