1. The problem statement, all variables and given/known data A bolt drops from the ceiling of a traincar which is acceleration northward at a rate of 2.5 m/s2. What is the acceleration of the bolt with respect a stationary train station. 2. Relevant equations Seems more qualitative to me, but d = V1t + (1/2)at2 could be relevant. 3. The attempt at a solution This question is just puzzling me. I'm assuming that if you were in the train station and saw the train, it'd be passing left to right. Or should I be thinking that the train has already passed the train station? This is a two part question, the first asking what the acceleration of the bolt is wrt the train car. That part is simple, I just get the resultant acceleration, by solving the vectors with Pythagorean theorem. I'm thinking that the acceleration from the stationary train station is the same. It's based on inductive reasoning, because if someone in a bus had an object in their hand and the bus passed stationary pedestrian (and they saw it the bus pass coming from the left of their vision, to the right) it'd be whatever velocity the bus was traveling at. So for the stationary train station, I'd think that the magnitudes would be the same, but the direction would be...different?