Cold water flowing at $$0.1$$ $$kg/s$$ is heated from $${20^ \circ }C$$ to $${70^ \circ }C$$ in a counter-flow type heat exchanger by a hot water stream flowing at $$0.1$$ $$kg/s$$ and entering at $${90^ \circ }C$$. The specific heat of water is $$4200$$ $$J$$($$kg$$ $$K$$) and density is $$1000$$ $$kg/{m^3}.$$ If the overall heat transfer coefficient $$U$$ for the heat exchanger is $$2000$$ $$W/\,\,\left( {{m^2}\,\,K} \right),$$ the required heat exchange area (in $${{m^2}}$$) is

In resistance seam welding, the electrode is in the form of a

Which of the following welding process results in the smallest heat affected zone

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