resistance spot welding is performed on two plates of $$1.5$$ $$mm$$ thickness with $$6$$ $$mm$$ diameter electrode, using $$15000$$ $$A$$ current for a time duration of $$0.25sec$$. assuming the interface resistance to be $$0.0001\Omega ,$$ the heat generated to form the weld is

During orthogonal cutting of mild steel with a $$10$$ degrees rake angle tool the chip thickness ratio was obtained as $$0.4.$$ The shear angle (in degrees) evaluated from this data is

For turning $$NiCr$$ alloy steel at cutting speeds of $$64m/min$$ and $$100m/min,$$ the respective tool lives are $$15min$$ and $$12$$ $$min.$$ The tool life for a cutting speed of $$144m/min$$ is

Tool life testing on a lathe under dry cutting conditions gave $$'n'$$ and $$'C'$$ of Taylor tool life equation as $$0.12$$ and $$130$$ $$m/min,$$ respectively. When a coolant was used, $$'C'$$ increased by $$10\% $$. The increased tool life with the use of coolant at a cutting speed of $$90$$ $$m/min$$ is