Plot the force vs. reduction in height curve in open-die forging of a cylindrical, annealed copper specimen 50 mm high and 25 mm in diameter, up to a reduction of 70%, for the cases of (a) no friction between the flat dies and the specimen, (b) μ = 0.25, and (c) μ = 0.5 . ignore barreling. use average-pressure formulas.