A disc of $$200$$ $$mm$$ outer and $$80$$ $$mm$$ inner diameter is faced at a feed of $$0.1$$ $$mm/rev$$ with a depth of cut of $$1$$ $$mm.$$ The facing operation is undertaken at a constant cutting speed of $$90$$ $$m/min$$ in a $$CNC$$ lathe. The main (tangential) cutting force is $$200$$ $$N$$

Assuming approach and over-travel of the cutting tool to be zero, the machining time in $$min$$ is

In a shaping process, the number of double strokes per minute is $$30$$ and the quick return ratio is $$0.6,$$ If the length of the stroke is $$250mm,$$ the average cutting velocity in $$m/min$$ is

In a single pass drilling operation, a through hole of $$15$$ $$mm$$ diameter is to be drilled in a steel plate of $$50mm$$ thickness. Drill spindle speed is $$500epm,$$ feed is $$0.2mm/rev$$ and drill point angle is $${118^ \circ }.$$ Assuming $$2mm$$ clearance at approach and exit, the total drill time (in seconds) is

During orthogonal machining of a mild steel specimen with a cutting tool of zero rake angle, the following data is obtained:
Uncut chip thickness $$=0.25$$ $$mm$$
Chip thickness $$=0.75$$ $$mm$$
Width of cut $$=2.5$$ $$mm$$
Normal force $$=950$$ $$N$$
Thrust force $$=475$$ $$N$$

The ultimate shear stress (in $$N/m{m^2}$$) of the work material is