So let's just remind ourselves. If we have, let's say our position is a function of time, so let's say x of t is position as a function of time, then if we were to take the derivative of that, so x prime of t, well, that's going to be the rate of change of position with respect to time or the velocity as a function of time. And if we were to take the derivative of our velocity, then that's going to be the rate of change of velocity with respect to time. Well, that's going to be acceleration as a function of time. So they give us velocity, so from velocity we can figure out acceleration. So let me just rewrite that. So we know that v of t is equal to negative t to the third power plus six t squared plus two t, and so from that we can figure out the acceleration as a function of time, which is just going to be the derivative with respect to t of the velocity.