Relvel

Relvel is a term that can refer to the concept of relative velocity in physics, though it is not a standard notation or widely recognized term. In informal discussions and some technical writings, relvel may be used as an abbreviated form of relative velocity—the velocity of one object as observed from another object's frame of reference.

In physics, relative velocity describes how fast and in what direction an object appears to move relative to another. If objects A and B have velocity vectors v_A and v_B measured in a common inertial frame, the relative velocity of A with respect to B is v_rel = v_A − v_B. The concept depends on the chosen reference frame and is essential in collision analysis, pursuit problems, and radar tracking. Relative velocity can be decomposed into components parallel and perpendicular to a line of sight, and it is used to determine closing speeds, approach angles, and time-to-collision estimates.

Beyond physics, Relvel may be encountered as a project or product name in niche software, simulations, or branding. There is no single, universally recognized entity named Relvel in established scientific literature, so any such usage is defined by its own documentation. In that sense, relvel functions as a contextual label rather than a formal scientific term.

See also: Relative velocity, Reference frame, Velocity.