[填空题]
In Problem 79 (Fig. 7–46), what is the upper wa(aee9gj 6frydv 680limit on9: b5mza846hxi /dilf +ptokq mass m if it is to rebound from M, slide up the incline, stop, slide down the incline, and collide wit94foapbq/x8k l+:zd5 ii6 hmth M again? kg (Let A represent mass m, and B represent mass M.)