Let's say that we know that the acceleration of a particle as a function of time is equal to 1. It's always accelerating at 1 unit per, and I'm not giving you time, but let's just say that we're thinking in terms of meters and seconds. This is 1 meter per second squared right over here. That's our acceleration as a function of time. Let's say we don't know the velocity expressions, but we know the velocity at a particular time, and we don't know the position expressions, but we know the position at a particular time. Let's say we know that the velocity at time 3, let's say 3 seconds, is negative 3 meters per second. Actually, I'm going to write the units here and make it a little bit.