For every action there is an equal and opposite reaction. what does this quote mean?

so it is said that every action has equal and opposite reaction

Explanation:

This is newton's III law which states that if some force is applied in the form of action force to an object then the same magnitude force is applied by the object on the source in reverse direction

so we can say that the reaction force is always applied by object in opposite direction

so in vector form we can say

so it is said that every action has equal and opposite reaction

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

not too sure thinking all accelerations are pointed down