The athlete performs the exercise "pulling the bar with a wide grip to the chin." Determine the support reaction R that occurs when the athlete lifts the barbell with an acceleration of a=6 m/s^2. The exercise is performed from a standing position, without leaving the support, moving the barbell along the body to the chin. The weight of the athlete M = 75 kg, the weight of the bar m = 20 kg. Take g=10 m/s^2.