Which pair of following statement is correct for orthogonal cutting using a single-point cutting tool?
$$P.$$ reduction in friction angle increases cutting force
$$Q.$$ Reduction in friction angle decreases cutting force
$$R.$$ Reduction in friction angle increases chip thickness
$$S.$$ Reduction in friction angle decreases chip thickness

During pure orthogonal turning operation of a hollow cylindrical pipe, it is found that the thickness of the chip produced is $$0.5mm.$$ The feed given to the zero degree rake angle tool is $$0.2mm/rev.$$ The shear strain produced during the operation is ___________

Two cutting tools are being compared for a machining operation. The tool life equations are:
$$\eqalign{ & \,\,\,\,\,\,\,\,\,\,\,\,Carbi{\mathop{\rm de}\nolimits} \,\,tool:\,\,\,\,\,\,\,\,\,\,\,\,V{T^{1.6}} = 3000 \cr & \,\,\,\,\,\,\,\,\,\,\,\,HSS\,\,tool:\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,V{T^{0.6}} = 200 \cr} $$

Where $$V$$ is the cutting speed in $$m/min$$ and $$T$$ is the tool life in $$min.$$ The carbide tool will provide higher tool life if the cutting speed in $$m/min$$ exceeds

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

The normal force acting at the chip-tool interface in $$N$$ is