A uniform board of mass m and length L is pivoted on one end and is supported in the horizontal position by a rope attached to the other end. Another rope, attached to the board a distance L/3 from the pivot point, is being pulled straight down with a constant force of magnitude F. Suddenly, the rope attached to the end of the board breaks. Find the angular acceleration alpha of the board immediately after the rope breaks. Express our answer in terms of the given quantities and appropriate constants. You may or may not use all given quantities.
Note 1. Let the pivot be the axis about which net torque and angular acceleration and moment of inertia all exist after the rope at distance L breaks.
Note 2. After the end rope breaks, the only existing forces are mg at distance 0.5 L ...
The answer gives the angular acceleration alpha of the uniform board, right after the rope breaks. Parameters of mass, length, and distance are given, with a constant force of magnitude, and, in using the properties of torques, the alpha is thus determined.