Final answer:
The magnitude of average velocity is largest during the first trial.
Step-by-step explanation:
The magnitude of average velocity is largest during the first trial.
To determine the magnitude of average velocity, we need to find the total displacement divided by the total time. The larger the displacement and the shorter the time, the greater the magnitude of average velocity.
In the first trial, the velocity of the first wave is given as the reference velocity. Since the velocity in the other trials is either the same or larger than the velocity of the first wave, the magnitude of average velocity is largest in the first trial.