Plot the force vs. reduction in height curve in open-die forging of a solid cylindrical, annealed copper specimen 2 in. high and 1 in. in diameter, up to a reduction of 70%, for the cases of (a) no friction between the flat dies and the specimen and (b) = 0.25. K = 315 MPa = 46,000 psi, n = 0.54 and Yf = (46, 000 psi) 0.54. In support of your answer, explain how friction affects forging force.