Find the resultant stress on the second plane

Question

At a point in a material under stress, the intensity of the resultant stress on a certain plane is 50 MN/m² (tensile) inclined at 30⁰ to the normal of that plane. (Refer fig. 2) The stress on a plane at right angles to this plane has a normal tensile component of intensity of 30MN/m². Find:

1. the resultant stress on the second plane
2. the principal planes and stresses
3. maximum shear stress and the plane on which it occurs

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