019 10.0 points An engineer in a locomotive sees a car stuck
on the track at a railroad crossing in front of
the train. When the engineer first sees the
car, the locomotive is 100 m from the crossing
and its speed is 12 m/s.
If the engineer's reaction time is 0.55 s,
what should be the magnitude of the mini-
mum deceleration to avoid an accident?
Answer in units of m/s².

Explanation:

Distance remaining after reaction time

s = s₀ - v₀t

s = 100 - 12(0.55) = 93.4 m

v² = u² + 2as

a = (v² - u²)/2s

a = (0² - 12²) / 2(93.4) = - 0.770877944...

|a| = 0.77 m/s²

it's when something is going so fast it makes a loud noise, breaking the sound barrier, for example: a jet makes a loud noise, not only cause of the jet but because they reached a point where they went so fast that you can year the noise from various parts, kinda like a police car, lets say the car was going   so fast that you hear the siren of the cop car right next to you, but the car is probably a mile a way, it's cos the siren was next to you a few seconds if you understand me