A uniform board is leaning against a smooth vertical wall. The board is at an angle above the horizontal ground. The coefficient of static friction between the ground and the lower end of the board is 0.790. Find the smallest value for the angle A, such that the lower end of the board does not slide along the ground.

A uniform board is leaning against a smooth vertical wall. The board is at an angle above the horizontal ground. The coefficient of static friction between the ground and the lower end of the board is 0.790. Find the smallest value for the angle A, such that the lower end of the board does not slide along the ground.