1. The problem statement, all variables and given/known data A stick is lying at rest against the wall. Which of the following statements is true? A) Friction must be present on both the wall and the floor surfaces. B) The wall surface must be rough, but the floor may be smooth. C) The floor surface must be rough, but the wall may be smooth. D) The wall and the floor surfaces can both be smooth. 2. Relevant equations None 3. The attempt at a solution I chose D. The answer is C. I know there's the weight of the stick acting downwards. The reaction force of the wall on the stick. The reaction force of the floor on the stick. Because the reaction of the wall ----> must have a horizontal component (even if it's not horizontal), so there should be a <---- force provided by the floor. But can't the floor just provide that by having a non-vertical reaction force?