The stone's altitude at time
is given by

where
is the acceleration due to gravity. The stone reaches the ground when
:

Answer:
The starting position of the runner.
Explanation:
When you look at the graph, you can see that the first point on the graph is twenty on the y-axis.
The runner starts at twenty, and ends at thirty.
Therefore, the runner starts at twenty on the y-axis, so it's the starting position of the runner.
Answer:
longitudinal wave
Explanation:
it is perpendicular to the direction of the wave
Answer:
I believe the answer for this question is D
Explanation:
I hope this helps and is correct