Time for another hypothetical.

Let's say you're at the gym making small talk. If another patron were to tell you "Gary sprinted 39.3 feet (12 meters) in three seconds today," they'd be giving you his *speed*, but not his *velocity*.

To calculate Gary's velocity, we'd need more information.

If our gym buddy said, "Gary sprinted 39.3 feet (12 meters) *west* in three seconds today," then we'd know about his direction of travel and be off to a good start.

The formula for calculating an object's velocity is as follows:

Here, the letters "v," "d" and "t" respectively denote "velocity," "displacement" and "time." In other words, **velocity = displacement divided by time**.

When using this formula, it's important to measure displacement in meters and time in seconds. For simplicity's sake, let's assume that old Gary ran to the west in a perfectly straight, 12-meter (32.8-foot) line, so his displacement equals the distance he traveled.

We also know that it took him three seconds to cover the gap between his starting and ending points.

Therefore, when we plug in the numbers, we get this:

Ergo, westbound Gary had an average velocity of 4 meters per second (13.12 feet per second).

(Phrasing matters here. All we've done is calculate Gary's average velocity; we haven't addressed the subject of instantaneous velocity, a phenomenon that puts its own twist on the formula broken down above.)