Answer:
0 m
Explanation:
Displacement is the shortest distance from one ppont to another. Here, the girl returns to the same spot after running. Hence, displacement is <u>0</u><u> </u><u>m</u>.
The frequency of the wave has not changed.
In fact, the frequency of a wave is given by:

where v is the wave's speed and
is the wavelength.
Applying the formula:
- In air, the frequency of the wave is:

- underwater, the frequency of the wave is:

So, the frequency has not changed.
The international system of units is the designated system of units used by scientist in every part of the world to keep data in the same form and measurements, this is to avoid confusion and the need to convert data when being shared. typically described in meters or kilometer over a time form usually seconds or hours.
Answer i dont even know im just putting this cus id ont care
Explanation: