Answer:
101.54m/h
Explanation:
Given that the buses are 5mi apart, and that they are both driving at the same speed of 55m/h, rate of change of distance can be determined using differentiation as;
Let l be the be the distance further away at which they will meet from the current points;
#The speed toward each other.

Hence, the rate at which the distance between the buses is changing when they are 13mi apart is 101.54m/h
The acceleration is 3.3 m/s2
Answer:
7 m .
Explanation:
For destructive interference
Path difference = odd multiple of λ /2
Wave length of sound from each of A and B.
= speed / frequency
λ = 334 / 172 = 2 m
λ/2 = 1 m
If I am 1 m away from B , the path difference will be
8 - 1 = 7 m which is odd multiple of 1 or λ /2
So path difference becomes odd multiple of λ /2.
This is the condition of destructive interference.
So one meter is the closest distance which I can remain at so that i can hear destructive interference.