Average vs. Instantaneous Velocity

Why do we use this word "average" in front of velocity? So far, you have only looked at objects traveling with a constant velocity so at any point along the motion, the velocity would be the same. What happens when the velocity is not constant? While we are not going to get into a full discussion as to why things move the way they move (that comes in the next unit), we still need to know how things move to describe motion.

Look at the animation. It shows a toy Lamborghini traveling at a non-constant velocity. Click the image below to view the animation.

Now, look at the following animation of the same car. In the explanation, take note of the difference between average velocity and instantaneous velocity. Click the image below to view the animation.

Our current mathematical model uses the average velocity, not instantaneous velocity. If you have an object that is moving with non-constant velocity, you have to solve for the average velocity before using the equation. Let’s extend our model to include objects that are not traveling at a constant speed.