a person $($m$=80$kg$)$ walks toward the edge of a beam$($M$=100$kg$,$ L$=4\mathrm{.}0$m$)$ that is hinged to a stable wall at its left end. the beam is supported at its other end by a cable, which makes an angle of $60$ degrees to the beam. $($a$)$ if the maximum tension the cable can withstand before breaking is $1200$N$,$ how far from the wall $($x$)$ can the person walk before the cable snaps? $($b$)$ when the person is this distance from the wall, what is the magnitude of the total supporting force of the hinge?