The effect of rake angle on the mean friction angle in machining can be explained by

A low carbon steel is to be welded by the manual metal arc welding process using a linear $$V$$-$$I$$ characteristic $$DC$$ power source.

The following data is available.
$$O.C$$ voltage of the power source $$=62V,$$
$$S.C$$ current for the setting used $$=130A,$$
ARC length $$=4mm,$$
Traverse speed of welding $$=15cm/min$$
Efficiency of heat input $$ = 85\% $$
The relation between the arc length $$L$$ in $$mm$$
and arc voltage $$V$$ is $$V=20+1.5L$$
Calculate the heat input into the work piece.

In an explosive welding process, the ..................... (maximum/minimum) velocity of impact is fixed by the velocity of sound in the ............. (flyer / target) plate material.

For resistance spot welding of $$1.5$$ $$mm$$ thick steel sheets, the current required is of the order