(s)(si units) a hot upset-forging operation is performed in an open die. initial diameter of the cylindrical work part = 30 mm, and its height = 50 mm. the part is upset to an average diameter = 45 mm. the work metal at this elevated temperature yields at 90 mpa. coefficient of friction at the diework interface = 0.40. determine (a) the final height of the part and (b) the maximum force in the operation.