(a) At a point in a material under stress, the resultant intensity of stress across a certain plan is 100 N/mm2 (compressive) inclined at 30o to its normal. On another plane the intensity of resultant stress is 75 N/mm2 (tensile) inclined at 45o to its normal. Determine theprincipal stress and their directions to the provided plane. Determine also the angle between the two planes.
(b) Figure shown the direct stress in three co-planer directions differing by 60o. Evaluate the directions and magnitude of principal stresses.