You calculate velocity by dividing the distance you've traveled by the time it took to travel that distance and specifying the direction of your movement.
Understanding Velocity
Velocity isn't just about speed; it's about speed and direction. This makes it a vector quantity, unlike speed, which is a scalar quantity.
The Formula
The formula for calculating velocity is:
Velocity (v) = Displacement (Δx) / Time (Δt)
- Displacement (Δx): The change in position. This is the straight-line distance between your starting point and your ending point, along with the direction.
- Time (Δt): The time interval over which the displacement occurred.
Example
Let's say you walk 10 meters east in 5 seconds. Your velocity would be:
v = 10 meters / 5 seconds = 2 meters per second east.
The crucial part is stating the direction (east). If you just said "2 meters per second," you'd be describing your speed, not your velocity.
What if your position doesn't change?
If your position remains the same, your displacement is zero. Therefore, your velocity is zero, regardless of how much you're moving in place. Running on a treadmill at a high speed doesn't result in a change of position. Since you do not actually travel anywhere, your displacement is zero.
Key Differences: Speed vs. Velocity
| Feature | Speed | Velocity |
|---|---|---|
| Definition | Rate at which an object covers distance. | Rate at which an object changes position. |
| Quantity Type | Scalar (magnitude only) | Vector (magnitude and direction) |
| Formula | Speed = Distance / Time | Velocity = Displacement / Time |
| Direction | Not specified | Specified |
| Example | 60 mph | 60 mph North |
In summary, to get your velocity, you need to know both how far you've moved from your starting point (displacement) and the time it took to get there, along with the direction of your movement.
