1. Displacement: This is the change in position of the object. It's not just the distance traveled, but also the direction. For example, if an object moves 5 meters to the east and then 5 meters to the west, its displacement is 0 meters.

2. Time: You need to know the time interval over which the displacement occurred.

Formula:

Velocity = Displacement / Time

Here are some additional things to consider:

* Direction: Velocity is a vector quantity, meaning it has both magnitude (speed) and direction. Make sure you note the direction of the displacement.

* Constant vs. Non-constant Velocity: If the object's velocity is constant, the above formula is sufficient. If the velocity is changing, you'll need to use calculus or other more advanced techniques to determine the instantaneous velocity at a specific point in time.

* Average vs. Instantaneous Velocity: The formula above gives you the average velocity over the given time interval. The instantaneous velocity is the velocity at a specific moment in time.

Example:

A car travels 100 km east in 2 hours. Its velocity is:

Velocity = 100 km (east) / 2 hours = 50 km/h (east)