Velocity is the rate at which an object changes its position over time. Velocity is a vector quantity, meaning it has both magnitude and direction. The magnitude of velocity is speed, which is the distance traveled per unit time. The direction of velocity is the direction in which the object is moving.
Velocity is an important concept in physics, as it can be used to calculate the motion of objects. For example, velocity can be used to calculate the time it will take an object to travel a certain distance, or to calculate the force that is acting on an object. Velocity can be measured using a variety of methods, including radar, GPS, and accelerometers.