+ 420 ksi 4 ksi PROBLEM 1 For the given state of stress, determine (a) the principal planes, (b) the principal stresses. 6 ksi A 60 MPa 25 MPa 40 MPa PROBLEM 2 For the given state of stress, determine (a) the orientation of the planes of maximum in-plane shearing stress, (b) the maximum in-plane shearing stress, (c) the corresponding normal stress. 60 MPa 20 MPa 40 MPa PROBLEM 3 For the given state of stress, determine the normal and shearing stresses after the element shown has been rotated through (a) 25° clockwise, (b) 10° counterclockwise.