A rigid bar AB having mass M$=1\mathrm{.}0$kg and length L$=0\mathrm{.}5$m is hinged at end A and supported at end B by a nylon cord BC $($Fig$.2).$ The cord has cross$-$sectional area A $=30$ mm$2,$ length b $=0\mathrm{.}25$ m$,$ and modulus of elasticity E $=2\mathrm{.}1$ GPa

If the bar is raised to its maximum height and then released, what is the

maximum stress in the cord