Just remember acceleration is just the rate of change of velocity. If acceleration is negative, that means the rate of change of velocity is negative. It's just going down. Anyway, how do we address this speed issue? How do we think about it? There's two scenarios. If our velocity is positive at time 5.5, so if we have a positive velocity, so let's say our velocity is 5 meters per second, although they don't give us units here, so I won't use units.