1. Displacement: This refers to the change in position of an object. It's not just the distance traveled, but also the direction.

2. Time: You need to know the time it took for the object to undergo the displacement.

3. Direction: Velocity is a vector quantity, meaning it has both magnitude (speed) and direction. You need to know the direction of the displacement.

In short: Velocity = Displacement / Time, and the direction must be specified.