Explanation:
Formula to calculate the angular momentum is as follows.
L = mvr
where, m = 65.5 kg
v = 5.13 m/s
r = 12 m
Therefore, calculate the angular momentum as follows.
L = mvr
= [tex]65.5 kg \times 5.13 m/s \times 12 m[/tex]
= 4032.18 [tex]kg m^{2}/s[/tex]
Therefore, we can conclude that the magnitude of the initial angular momentum of the system by treating the astronauts as particles is 4032.18 [tex]kg m^{2}/s[/tex].