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