1. The problem statement, all variables and given/known data A plank of wood is attached onto the wall by a hinge. The blank is inclined at an angle of 30 degrees to the horizontal and is held stationary by a rope which is attached at the opposite end onto the wall. Label the three forces acting on the plank 2. Relevant equations None 3. The attempt at a solution I have attached a diagram I have drawn of the problem and my attempt. The tension and weight force are easy but the I am unsure about the third force exerted by the hinge/wall. The answer in the back of the book says that the third force is "the reaction force from the hinge/wall passing through the point where the weight arrow meets the tension arrow". I have no idea what or where this point is they are on about. I approached it by arguing that the hinge must exert equal and opposite forces to the weight and tension. I have drawn a vector diagram on the attachment to and labelled the third force. Is this correct and can someone please explain what this point is they are on about - there is no point where they cross? Thanks!