Physicists use some basic terms when they look at motion. How fast an object moves, its speed or Velocity, can be influenced by forces. (Note: Even though the terms 'speed' and 'velocity' are often used at the same time, they actually have different meanings.) Acceleration is a twist on the idea of velocity.
Expungement is the legal process by which a court removes or erases all records of a criminal conviction, even if it is a felony conviction. Your conviction will not simply disappear on its own even if you wait 10 or 20 years - you have to take action (see how long does a felony stay on your record).
1 If you were under 18 at the time of the offense and are now over 18, you can get it expunged six months after paying your fine.  If you were over 18 at the time of the offense, you must have a five-year period where you were never arrested before you can get an expungement.