Speed, Velocity, and Acceleration https://volleyballcamps.wordpress.com/tag/off-speed-volleyball/ "Speed is a scalar quantity that refers to "how fast an object is moving. Speed can be thought of as the rate at which an object covers distance." Which is also the distance traveled over time. "Velocity is a vector quantity that refers to the rate at which an object changes its position." Which is also the displacement over time. "Acceleration is a vector quantity that is defined as the rate at which an object changes its velocity." It can also be calculated as velocity over time.     With a better understanding of speed, velocity, and acceleration you can see why teams dig, set, and spike. Both slow and fast speeds can be used to your advantage in volleyball. When the opponent serves a ball traveling at a high speed, you can slow the ball down by digging to the setter. The setter then sets the ball to the hitter with a slow ball so that the hitter has enough time to adjust and hit the ball. However experienced teams could set the outside hitter a quick ball "shoot set" horizontally so that the hitter could quickly hit the ball, giving opponents almost no time to react. This process of the ball changing velocity is acceleration.