By application of tensile force, the cross sectional area of bar $$' P '$$ is first reduced by $$30\% $$ and then by an additional $$20\% $$. Another bar $$'Q'$$ of the same material is reduced in cross sectional area by $$50\% $$ in a single step by applying tensile force. After deformation, the true strain in bar $$'P'$$ and bar $$'Q'$$ will, respectively, be

A $$10mm$$ diameter annealed steel wire is drawn through a die at a speed of $$0.5/sec$$ to reduce the diameter by $$20\% $$. The yield stress of the material is $$800MPa.$$

Neglecting friction and strain hardening, the stress required for drawing (in $$MPa$$) is

The maximum possible percentage reduction in area per pass during wire drawing of an ideal plastic material without friction is of the order of

A copper strip of $$200$$ $$mm$$ width and $$30$$ $$mm$$ thickness is to be rolled to a thickness of $$25$$ $$mm.$$ The roll of radius $$300$$ $$mm$$ rotates at $$100$$ $$rpm.$$ The average shear strength of the work material is $$180$$ $$MPa.$$ The roll strip contact length and the roll force are