A steel rod of length `6.0 m` and diameter `20 mm` is fixed between two rigid supports . Determine the stress in the rod, when the temperature increases by `80^@`C if
(a)the ends do not yield (b) the ends yield by 1mm
Take `Y=2.0xx10^(6) kg//cm^(2)`and`alpha=12xx10^(-6) per ^@C.`