Acting at a point on a horizontal plane in a loaded machine part are normal stress and...

Acting at a point on a horizontal plane in a loaded machine part are normal stress and a (negative) shearing stress. One principal stress at the point is 10 MPa (tensile), and the maximum shearing stress is of magnitude 50 MPa. Find, by the use of Mohr’s circle, (a) the unknown stresses on the horizontal and vertical planes and (b) the unknown principal stress. Show the principal stresses on a sketch of a properly oriented element.