The red vector represents the weight of the block and the blue vector represents the normal force of the ramp on the block (Note: The normal force is shown with a fatter arrow so you can see it better...The red vector represents the weight of the block and the blue vector represents the normal force of the ramp on the block (Note: The normal force is shown with a fatter arrow so you can see it better). When the board has a mass, there are four forces that act on the board: the weight of the box, the weight of the board, and the forces of the supports.