McAdoo scored in double figures in 21 of the first 22 games for North Carolina before battling a sore back and scoring in single figures in each of his past three games.
The sophomore forward was sharp against the Yellow Jackets. He had 15 points in the first half and scored the final basket in the 12-0 run that gave North Carolina (18-8, 8-5 Atlantic Coast Conference) a 59-41 lead with 8:47 remaining. The Tar Heels stretched the lead to 22 points at 66-44.
Leslie McDonald, who had four 3-pointers, had 15 points.
Marcus Georges-Hunt and Chris Bolden scored 12 points apiece for Georgia Tech (14-11, 4-9).
The Yellow Jackets had won four of seven games since a 79-63 loss at North Carolina on Jan. 23.
North Carolina center Joel James missed his third consecutive game with a concussion. James' injury helped open the way for coach Roy Williams to move to a four-guard lineup and shortened rotation.
P.J. Hairston, who scored a career-high 29 points while making six 3-pointers in the Tar Heels' 93-81 win over Virginia on Saturday, opened the game with another 3. North Carolina then missed its next five shots during Georgia Tech's 8-0 run.
The Yellow Jackets led 19-16 following a basket by Georges-Hunt.
A three-point play by McAdoo started a string of seven unanswered points for the Tar Heels.
Georgia Tech missed each of its six free throws in the first half, matching the margin of its 36-30 deficit.
Kammeon Holsey, who had 10 points, missed the first of two free throws early in the second half to leave the Yellow Jackets 0 for 7 from the line, but he made the second attempt, bringing a loud cheer from the crowd. Overall, Georgia Tech made only 4 of 11 free throws.
Hairston, who made only 4 of 15 shots, finished with 10 points.
Among the former Georgia Tech stars in the stands for the game: coach Bobby Cremins, Miami Heat forward Chris Bosh, Atlanta Hawks guard Anthony Morrow and Detroit Lions wide receiver Calvin Johnson.