Answer:
the distance between the submarine and the ocean floor is 11,250 m
Explanation:
Given;
speed of the wave, v = 1500 m/s
time of motion of the wave, t = 15 s
The time taken to receive the echo is calculated as;

Therefore, the distance between the submarine and the ocean floor is 11,250 m
Answer:

West
Explanation:
m = Mass of car = 
t = Time = 9 seconds
u = Initial velocity = 30 m/s
v = Final velocity = 0
Impulse is given by

The magnitude of the total impulse applied to the car to bring it to rest is
.
The direction is towards west as the sign is negative.
true if you are refering to the desing of the experimnt as it does identify the variable