1. The problem statement, all variables and given/known data Suppose I throw a ball at a wall parallel to its x-axis. At the moment it hits the wall, what forces are acting upon the ball? 2. Relevant equations None. Relevant assumptions: ignore any spin on ball. 3. The attempt at a solution I think they'll be: - gravity acting in the negative y-axis direction - friction acting in the positive y-axis direction - friction acting in the negative x-axis direction. Friction may be kinetic or static depending on whether ball slips while bouncing? Have I missed anything? Or included something falsely? I'm pretty sure that there's a friction force in the negative y-axis direction, but not entirely sure, since the ball's path will be arcing downwards with gravity.