Speed and velocity

Science

Definition

Speed is the rate at which an object covers distance and is a scalar quantity (magnitude only). Velocity is a vector quantity that includes both the speed and the direction of motion. An object can have constant speed but changing velocity if its direction changes.

Examples

  • A car's speedometer reading 60 mph (speed) versus saying '60 mph north' (velocity)
  • A runner completing a lap around a 400 m track in 60 s has speed but zero average velocity
  • The International Space Station traveling at 7.66 km/s in a specific orbital direction
Key Fact

Speed = distance/time; Velocity = displacement/time (vector)

Related Terms

Displacement and velocity Acceleration Motion graphs Kinematic equations

Study This Concept

Practice speed and velocity with free review games in these units:

Physics Unit 1: Motion and Kinematics