Answer:
The toy must calculate the person's speed/velocity
Step-by-step explanation:
Since the school toy given to Henry can be used to tell how fast someone is moving, the toy must be able to calculate the person's speed/velocity using the average distance covered by the person divided by time taken to cover the distance; average distance ÷ time taken.
The toy must be able to determine the parameters (average distance and time taken) in order to be able to calculate the person's speed/velocity