The way the sound waves hit your eardrums and they are moved by the sound pressure. Then your brain takes over from there.
Hello
The bullet is moving by uniformly accelerated motion.
The initial velocity is

, the final velocity is

, and the total time of the motion is

, so the acceleration is given by
where the negative sign means that is a deceleration.
Therefore we can calculate the total distance covered by the bullet in its motion using

So, the bullet penetrates the sandbag 1.8 meters.
Weak winds that blow for short periods of time with a short fetch.
Dependent variable is your answer.