The normal stress on the oblique plane is

Question

Two principal tensile stresses of magnitude 40 MPa and 20 MPa are acting at a point across two perpendicular planes. An oblique plane, makes an angle of 30⁰ with the major principal plane. The normal stress on the oblique plane is              

         (a) 8.66 MPa                      (b) 17.32 MPa

         (c) 35.0 MPa                      (d) 60.0MPa