Speed and velocity both are used to be as the words meaning the same when used in normal day to day situations . However the physicists out there treat those as different and technically there are many differences between them . Below are the key differences between the two .

Speed | Velocity |
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Speed is defined as the rate of change of distance per unit time . | Velocity is defined as the rate of change of displacement per unit time . |

Speed is a scalar quantity . It has only magnitude . | Velocity is a vector quantity . It has both magnitude and direction . The scalar absolute value (magnitude) of velocity is called "speed" . |

When something moves in a circle and returns to its starting point, its average speed is circumference divided by time taken . | When something moves in a circle and returns to its starting point, its average velocity is zero . |

Example : If a car is said to travel at 90 km/h, its speed has been specified. | If the car is said to move at 90 km/h to the south, its velocity has now been specified. |

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