A beam of I section, 6 m long, has an overall depth of 254 mm. The flanges are 152 mm wide and 25.4 mm thick. The web thickness is 12.7 mm (I = 110.4 x 106 mm). If the beam carries a uniformly distributed load of 400 kN in total, and is simply supported at its ends, calculate the maximum shear stresses in the web and flanges at a section 1.2 m from one end.