Velocity is a vector quantity, which means that it has both magnitude and direction. Instantaneous speed, on the other hand, is a scalar quantity, which means that it only has magnitude.
The magnitude of velocity is the speed of the object, while the direction of velocity is the direction in which the object is moving. Instantaneous speed is simply the speed of the object at a given instant in time.
Velocity can be calculated by dividing the displacement of an object by the time interval over which the displacement occurred. Instantaneous speed can be calculated by taking the limit of the average speed as the time interval approaches zero.
Velocity is a more useful measure of motion than instantaneous speed because it takes into account the direction of motion. For example, if two objects are moving at the same speed, but one object is moving north and the other object is moving south, then their velocities are different.
Here is a table summarizing the key differences between velocity and instantaneous speed:
| Feature | Velocity | Instantaneous Speed |
|---|---|---|
| Vector or scalar | Vector | Scalar |
| Magnitude | Speed | Speed |
| Direction | Yes | No |
| Calculation | Displacement / time interval | Limit of average speed as time interval approaches zero |
| Usefulness | More useful | Less useful |
