In a multipass rough-turning operation the tool life is observed to obey an equation t = v=f-08a-01 where u, f, and a, are the cutting speed, feed, and depth of cut, respec- tively, in SI units. The system normally operates with u = 1 m/s, f = 0.5 mm, and a, = 10 mm. Estimate the effect (percent increase or decrease) on tool life, cutting force, and power of doubling the metal removal rate by increasing (a) the speed, (b) the feed, (c) the depth of cut.