B it’s the most logical answer
Answer:
5 m/s²
Explanation:
Given:
v₀ = 0 m/s
v = 40 m/s
t = 8 s
Find: a
a = (v − v₀) / t
a = (40 m/s − 0 m/s) / 8 s
a = 5 m/s²
When air is blown into the open pipe,
L = 
where nis any integral number 1,2,3,4 etc. and λ is the wavelength of the oscillation
⇒λ=
Note here that n=1 is for fundamental, n=2 is first harmonic and so on..
⇒ third harmonic will be n=4
Given L=6m, n=4, solving for λ we get:
λ=
=3m
Relationship of frequency(f), velocity of sound (c) and wavelength(λ) is:
c=f.λ Or f= 
⇒f=
≈115 Hz
<span>First of all, the bolts wont hit the ground at equal time intervals because each bolt is constantly increasing. Therefore, the top will have different velocity with the bottom bolt at all times. this means that the bolts will speed up more as they are higher which will make the interval time shorter. therefore, the time will decrease</span>