What is the key difference between speed and velocity?

The key difference between speed and velocity lies in the inclusion of direction in the definition of velocity. Speed is defined as the rate of motion and is a scalar quantity, meaning it only considers how fast an object is moving regardless of its direction. On the other hand, velocity is a vector quantity that includes both speed and direction.

In this context, identifying speed as a rate of motion without direction is crucial. It highlights that while speed measures how quickly something is moving, it does not provide any information about the path or direction of that movement. This distinction is fundamental in fields such as physics and kinesiology, where understanding the nature of movement is important for assessment and evaluation.

For instance, if a car travels at 60 miles per hour, that figure represents its speed. However, if we say the car is traveling north at 60 miles per hour, we have defined its velocity. This is why the correct answer focuses entirely on the nature of speed in relation to direction.