In trying to lift sandbag B, attached to a lightweight rope as in the figure below, a worker at the top of the scaffolding places his tools and lunch kit into box A so that the entire mass of box A is now 80 kg. If the sandbag is 65 kg, find its speed as it hits the scaffolding. Assume that the sandbag starts from rest, and that the pulleys have negligible mass and friction. 4.2 m B 65 kg 80 kg