An aluminium cube of $$10$$ $$cm$$ side has to be cast along with a cylindrical riser of height equal to its diameter. The riser is not insulated on any surface. If the volume shrinkage of aluminium during solidification is $$6\% $$, calculate shrinkage volume of cube on solidification and minimum size of the riser so that it can provide the shrinkage volume.

In $$DC$$ welding, the straight polarity (electrode negative) results in

A milling cutter having $$8$$ teeth is rotating at $$150$$ $$rpm.$$ If the feed per tooth is $$0.1$$ $$mm,$$ the speed in $$mm$$ per minute is

A shaft of diameter $${20^{\matrix{ { + 0.05} \cr { - 0.15} \cr } }}\,\,mm$$ and a hole of diameter $${20^{\matrix{ { + 0.20} \cr { + 0.10} \cr } }}\,\,mm$$ when assembled would yield.