Could someone help me with this problem? I appreciate it! A uniform plank of mass M and length 2L is resting on a frictionless floor and leaning against a frictionless vertical wall. It is held steady by a massless string connecting the lower end of the plank to the base of the wall. The angle between the floor and the plank is theta. Calculate the acceleration of the upper end of the plank immediately after the string is cut, and the angle theta at which the upper end of the plank first separates from the wall. My prof. said that the plank would separate from the floor at about 2/3 of the original height where the plank was leaning against the wall. Thank you very much in advance!!!