A box of books is initially at rest a distance D = 0.530 m from the end of a wooden board. The coefficient of static friction between the box and the board is ?s = 0.300, and the coefficient of kinetic friction is ?k = 0.256. The angle of the board is increased slowly, until the box just begins to slide; then the board is held at this angle. Find the speed of the box as it reaches the end of the board.