Answer:
The time taken is 
Explanation:
From the question we are told that
The speed is 
The length of the tennis court 
Generally the time taken is mathematically represented as

=> 
The disturbance does not have a specific motions
Answer:
1. v = 6.67 m/s
2. d = 9.54 m
Explanation:
1. To find the horizontal velocity of the rock we need to use the following equation:
<u>Where</u>:
d: is the distance traveled by the rock
t: is the time
The time can be calculated as follows:
<u>Where:</u>
g: is gravity = 9.8 m/s²
Now, the horizontal velocity of the rock is:
Hence, the initial velocity required to barely reach the edge of the shell below you is 6.67 m/s.
2. To calculate the distance at which the projectile will land, first, we need to find the time:

So, the distance is:
Therefore, the projectile will land at 9.54 m of the second cliff.
I hope it helps you!
C. 4 N is the answer if not then i be dumb!!!