A 4.3-m long plank with a weight of 164 N is place on a dock with 1.4 m of its length extended over the water. The plank is uniform in density. A boy with a weight of 141 N is standing on the plank and moving out slowly from the edge of the dock. How far from the edge of the dock can the boy move until the plank is just on the verge of tipping?