What is the difference between speed and velocity?

The concept of speed and velocity is fundamental in physics, particularly in understanding motion. Speed is defined as how fast an object is moving, expressed as a scalar quantity. This means it only considers the magnitude of motion without any regard for direction. For instance, if a car travels at 60 kilometers per hour, that is its speed.

On the other hand, velocity is a vector quantity. This means it not only includes the magnitude of the movement (how fast the object is moving) but also specifies the direction of the object's movement. For example, if that same car is traveling north at 60 kilometers per hour, this description provides a complete picture of the object's motion, which is its velocity.

Thus, the distinction made in the correct answer highlights that while speed simply quantifies how fast an object is moving, velocity incorporates both the speed and the directional aspect of that movement, making it a more comprehensive measure of motion.