The speed of an object does not require a direction to be considered, it simply has a value and unit, for example, 27 \(m\,s^{-1}\). Velocity is a vector quantity which requires a value, unit and ...

Acceleration close accelerationThe rate of change in speed (or velocity) is measured in metres per second squared. Acceleration = change of velocity ÷ time taken. is the rate of change of velocity. It ...