1. The problem statement, all variables and given/known data "Assume that a train is traveling at 65 cm/s, and the track has radius 20cm. What is the magnitude of the train's average acceleration as the train goes from the tree marked A to the next tree B, located exactly 1/4 of the way around the track from tree A? [Hint: This question is not asking for the train's centripetal acceleration.]" 2. Relevant equations Equations of motion of object moving in circle, using ω,∝, θ. aavg=(vf-vi)/Δt 3. The attempt at a solution The answer is given to be 190 cm/s2 but why wouldn't it be zero? Maybe I'm misunderstanding the question, but if it doesn't want centripetal acceleration, it must mean tangential acceleration. And I thought that only the direction of tangential velocity changes, not magnitude. I also included a picture.