Two wooden planks each in thick and 1 / 2 in. thick and 9 in. wide, are joined by the dry mortise joint shown. Knowing that the wood used shears off along its grain when the average shearing stress reaches 1.20 ksi, determine the magnitude P of the axial load that will cause the joint to fail. Two wooden members of uniform rectangular cross section of sides a = 100 mm and b = 60 mm are joined by a simple glued joint as shown. Knowing that the ultimate stresses for the joint are sigma U = 1.26 MPa in tension and tau U = 1.50 MPa in shear and that P = 6 kN, determine the factor of safety for the joint when (a) alpha = 20degree, (b) 35degree, (c) alpha = 45degree. For each of these values of alpha, also determine whether the joint will fail in tension or in shear if P is increased until rupture occurs.