I thinks its He uses proof to show the evidence is relevant. But im not totally positive on it hope this helps
Answer:
The sound intensity of train is 1000 times greater than that of the library.
Explanation:
We have expression for sound intensity level,

A train whistle has a sound intensity level of 70 dB
We have

A library has a sound intensity level of about 40 dB
We also have

Dividing both equations

The sound intensity of train is 1000 times greater than that of the library.
Answer:
a = 2 [m/s²]
Explanation:
To be able to solve this problem we must make it clear that the starting point when the time is equal to zero, the velocity is 5 [m/s] and when three seconds have passed the velocity is 11 [m/s], this point is the final point or the final velocity.
We can use the following equation.

where:
Vf = final velocity = 11 [m/s]
Vo = initial velocity = 5 [m/s]
a = acceleration [m/s²]
t = time = 3 [s]
![11 = 5 + a*3\\6=3*a\\a= 2[m/s^{2} ]](https://tex.z-dn.net/?f=11%20%3D%205%20%2B%20a%2A3%5C%5C6%3D3%2Aa%5C%5Ca%3D%202%5Bm%2Fs%5E%7B2%7D%20%5D)
Line spectra are obtained when individual elements are heated using a high-voltage electrical discharge. This heating causes excitation of the element and a subsequent emission of distinct lines of colored light are obtained. Each element has its own unique emission line spectrum; therefore, if any of the tested substances were the same, their spectra would match. However, this is not the case so none of the substances are the same.
Answer:
23.0 s
Explanation:
Given:
v₀ = 0 m/s
v = 19.8 m/s
a = 4.80 m/s²
Find: Δx and t
v² = v₀² + 2aΔx
(19.8 m/s)² = (0 m/s)² + 2 (4.80 m/s²) Δx
Δx = 40.84 m
v = at + v₀
19.8 m/s = (4.80 m/s²) t + 0 m/s
t = 4.125 s
The elevator takes 40.84 m and 4.125 s to accelerate, and therefore also 40.84 m and 4.125 s to decelerate.
That leaves 291.3 m to travel at top speed. The time it takes is:
291.3 m / (19.8 m/s) = 14.71 s
The total time is 4.125 s + 14.71 s + 4.125 s = 23.0 s.