# Help me for Instantaneous Velocity

1. Aug 23, 2004

### EngTechno

can you explain me Instantaneous Velocity in simplest form?

2. Aug 24, 2004

### krab

The average velocity over a time interval is the distance traveled divided by the time interval. The instantaneous velocity is the limiting case, where the time interval approaches zero.

3. Aug 24, 2004

### robphy

Instantaneous velocity can be thought of as "[the vector quantity with magnitude] what your speedometer reads right now, together with the direction your car is pointing".

On a displacement-vs-time graph, you can visualize krab's definitions as
• average-velocity="the slope of a line-segment with endpoints at the start and end of the time-interval of interest"
• instantaneous-velocity="the slope of the tangent-line at the instant of interest"

It's good to remember these prepositional phrases
• average-velocity over a specific time-interval (you need to specify two times [better: two events])
• instantaneous-velocity at a specific instant (you need to specify one time [better: one event])