Question: A 7750 kg rocket blasts off vertically from the launch pad with a constant upward acceleration of 2.35 m/s^2 and feels no appreciable air resistance. When it has reached a height of 555 m , its engines suddenly fail so that the only force acting on it is now gravity. Part B: How much time after engine failure will elapse before the rocket comes crashing down to the launch pad? So, I understood Part B to mean: calculate the time from 555 m, when the engines fail, to the max height, when velocity=0. However, they are looking for the time from when the engines shuts off, 555 m, to when it crashes. I feel like Part B is ambiguous... we use MasteringPhysics and the book is great, but it seems like it was written in a lazy way. Maybe it's just me. What do you think?