Answer:
j
Explanation:
x = 4 t^2 - 2 t - 4.5
Position at t = 3 s
x = 4 (3)^2 - 2 (3) - 4.5 = 25.5 m
Velocity at t = 3 s
v = dx / dt = 8 t - 2
v ( t = 3 s) = 8 x 3 - 2 = 22 m/s
Acceleration at t = 3 s
a = dv / dt = 8
a ( t = 3 s ) = 8 m/s^2
When is the velocity = 0
v = 0
8 t - 2 = 0
t = 0.25 second
When is the position = 0
x = 0
4 t^2 - 2 t - 4.5 = 0

t = 1.4 second
Answer:
The frequency of the beats is 43.6408 kHz
Explanation:
Given:
f = frequency = 39.6 kHz
vc = speed of the car = 35 m/s
vs = speed of the sound = 343 m/s
Question: What is the frequency of the beats, f' = ?
As the car moves towards the source, the frequency of the beats

An equation can be dimensionally correct but that does not mean that it is physically correct. Explanation is given in the photo.
I believe a but none sound like they’d build a laser
Answer:
carbon dioxide
Explanation:
In addition to carbon dioxide, discussed below, coal plants all produce the following pollutants: Sulfur dioxide, which leads to acid rain. Coal combustion is the leading source of US sulfur dioxide emissions. Nitrogen oxides, key contributors to ground-level ozone (smog) and respiratory illnesses.