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

Match the following materials with their most appropriate application:

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 shear angle and shear force, respectively, are