What is the key difference between velocity and speed?

The distinction between velocity and speed is crucial in understanding motion in physics. Velocity is defined as a vector quantity, which means that it has both magnitude and direction. For instance, when you say a car is traveling at 60 kilometers per hour to the north, you are providing both the speed (60 kilometers per hour) and the direction (north)—this is indicative of velocity.

On the other hand, speed is a scalar quantity, which means it only involves magnitude and lacks any directional component. For example, when you refer to a car's speed as simply 60 kilometers per hour, it provides no information about the direction of the car's movement.

This difference highlights the fundamental ways in which we describe motion. Speed gives us the rate at which an object covers distance, while velocity gives us a fuller picture by incorporating the direction of that distance traveled. Hence, the key difference encapsulated in the correct answer emphasizes that velocity includes direction along with magnitude, while speed does not.