An athlete performs the exercise "wide$-$grip barbell upright row to the chin." Determine the support reaction R that occurs at the moment the athlete lifts the barbell with an acceleration of a$=4$m$/$s$2.$ The exercise is performed from a standing position, without losing contact with the support, moving the barbell along the body to the chin. The athlete's mass is M$=82$kg$,$ and the barbell's mass is m$=30$kg$.$ Assume g$=10$m$/$s$2.$