Common Data:
In orthogonal turning of a bar of 100mm diameter with a feed of 0.25mm/rev, depth of cut of 4mm and cutting velocity of 90m/min, it is observed that the main (tangential) cutting force is perpendicular to the friction force acting at the chip-tool interface. The main (tangential) cutting force is 1500N.
The orthogonal rake angle of the cutting toll in degree is