Final answer:
With the provided information, it is not possible to calculate the time duration for the change in acceleration from -7.0 m/s² to -12.5 m/s² for the leaf.
Step-by-step explanation:
The question involves calculating the time it takes for a leaf to change its acceleration from -7.0 m/s2 to -12.5 m/s2. Unfortunately, there is not enough information provided to accurately calculate the time duration for the change in acceleration. To determine the time, we would need either the distance over which the acceleration changes or the total time the leaf has been falling. As it stands, we cannot solve this problem with the given information.