The voltage-arc length characteristics of a power source is $$V=20+40L,$$ where $$V=$$ operating voltage in volts and $$L=$$ arc length in $$cm.$$ The open circuit voltage and short circuit current for arc lengths ranging from $$3$$ to $$5mm$$ and current from $$400$$ to $$500$$ amps during welding operation are

In a cutting test with $$0.3mm$$ flank wear as tool failure criterion, a tool life of $$10min$$ was obtained at a cutting velocity of $$20m/min.$$ Taking tool life exponrent as $$0.25,$$ the tool life in minutes at $$40m/min$$ of cutting velocity will be

A work-piece of $$2000$$ $$mm$$ length and $$300$$ $$mm$$ width was machined by a planning operation with the feed set at $$0.3$$ $$mm/stroke.$$ If the machine tool executes $$10$$ double strokes/min, the planning time for a single pass will be

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