Question

Consider the following statements:
If the planes at right angles carry only shear stress of magnitude q in a certain instance, then the
1. diameter of Mohr's circle would be equal to 2q.
2. centre of Mohr's circle would lie at the origin
3. Principal stresses are unlike and are of magnitude q each
4. angle between the principal plane and the plane of maximum shear would be 45°
Which of the above statements are correct?

• A. 1, 2 and 3 only
• B. 1, 2 and 4 only
• C. 3 and 4 only
• D. 1, 2, 3 and 4

Answer 1

The correct option is D 1, 2, 3 and 4


Its a case of pure shear. Hence Mohr's circle is as shown
Diameter of Mohr's circle = 2q
Centre is at origin
Principal stress are q and -q.
Hence they are equal in magnitude but unlike in direction.
Angle between normal to principal plane and normal to maximum shear is 90° in Mohr's circle.
so it would be 45°.