Identify the correct classification of speed.

Speed is classified as a scalar quantity because it only has magnitude, meaning it is described solely by a number indicating how fast an object is moving without any direction associated with it. In contrast, vector quantities, such as velocity and acceleration, possess both magnitude and direction.

Velocity refers to the speed of an object in a specific direction, while acceleration indicates the rate of change of velocity over time. Density is a different concept entirely and is not classified as either a vector or scalar regarding the context of speed. Thus, identifying speed correctly as a scalar highlights its fundamental characteristic of representing how fast something is moving, independent of its direction of travel.