Which of the following measures is associated with the speed of waves?

Velocity is the measure associated with the speed of waves because it directly refers to how fast the wave propagates through a medium. In wave physics, velocity is defined as the distance a wave travels per unit of time, which is typically expressed in meters per second (m/s). Understanding that velocity encompasses both the speed and direction of wave travel is crucial to grasping how waves move.

In contrast, amplitude refers to the height of the wave, indicating its intensity or power but not its speed. Frequency describes how many wave cycles occur in one second, typically measured in hertz (Hz), but again does not directly dictate speed. Wavelength represents the distance between successive crests or troughs of a wave, influencing the distance over which the wave oscillates but is not a direct measure of how fast the wave travels. Therefore, among these terms, velocity specifically denotes the speed, making it the correct answer.