Speed and Velocity
- Speed is a scalar. It is the magnitude of the velocity.
- Velocity, the rate of change of position, is a vector that
represents how fast, and in what direction, something is traveling.
| Average velocity:
vav |
= |
| Δx
|  |
| Δt
|
|
= |
| xf - xi
| |
| tf - ti
|
|
| Instantaneous velocity: v
|
= |
| dx
| |
| dt
|
|
The instantaneous velocity is the slope of the line on a position-versus-time graph.
If the velocity is constant the instantaneous velocity is equal to the average velocity.
Integrating the last equation, the displacement is given by:
| Displacement: Δx
|
= |
∫ |
v(t) dt |