Most all calculations rely on using velocity measurements in one way or another. The higher the velocity the quicker an object travels between two locations. Phrases like, how fast and how quickly, are used to describe velocity. Often the word speed is substituted for the word velocity. But the two are different.
Velocity is actually speed with direction.
18 Velocity differs from speed in that velocity tells not only the speed at which a roller coaster is moving but also its direction. There are two ways to experience weightlessness. In other words, accelerate to the Earth speeding up 22 mph every second in the air. In order for a person to feel weight, a person must sense the reaction force of the ground pushing in the opposite direction of gravity. In the absence of the reaction force a person will sink through the ground.