HOLLYWOOD — The Academy of Motion Picture Arts & Sciences’ documentary branch has elected Michael Apted and Arthur Dong to join Frieda Lee Mock on the board of governors.Election has been anticipated since June, when the board voted to grant the year-old docu arm a full complement of three governors. Since the branch formed in January 2001, it has held one rep on the board, Mock, who was elected to a three-year term. Apted will serve a three-year term and Dong a one-year term. With two years to go on Mock’s term, the branch is now positioned to elect or re-elect one governor each year, as do each of the other 13 branches. Board will meet in its new configuration with 42 members for the first time Aug. 8.