A cylindrical workpart with diameter 2.5 and height 2.5 in is upset forget in an open doe to a height 1.5 in, Coefificent of friction at the die work interface =0.10. The work material has a flow curve defuined by K = 40,000 lb/in.2 and n = 0.15. Determine the instantaneous force in the operation (a) just as the yield point is reached (yield strain = 0.002), and at a height (b) h = 1.8 in.