1. The problem statement, all variables and given/known data Which one of these motions is at constant acceleration? A) A car moving at a constant speed and constant direction. B) A train making stops along its route. C) A moon orbiting a planet. 2. Relevant equations 3. The attempt at a solution I believe that A is an acceptable answer, since the car is at a constant acceleration of zero. My teacher says C is the only correct answer. Thank you for your input!