A uniform beam of length L = 20.0 m and m = 60 kg is supported on points A and B, as shown in the figure.\fa) [10 pts] Find the maximum mass of a person who could walk to the extreme end D without tipping the beam. Hint: If the beam is just about to tip, with the person of maximum mass at point D, what then can you say about the value of one of the two normal forces?b) [7 pts] Find the forces that the supports A and B exert on the beam when a person whose mass is that found in part (a) is standing at point D