The startle reflex.
It is the alternator....
it just does...A loud noise makes you jumpbecausethere is a part of your ear that helps you to balance and when disrupted you jump
The fuel in the cylinders exploding
When lighting strikes it causes a cavity or vacuum in the air the loud noise is caused by the vacuum collapsing. as an example popping a plastic bag cause the same effect.
A little kid in the trunk with a hammer
Wheel bearing
The loud freewheel noise in a bicycle is typically caused by worn out or dirty freewheel components. This noise can be fixed by cleaning and lubricating the freewheel, or replacing it if necessary.
How is that related to gorrilas? A carp and a gorrilla are NOTHING alike
Noise is a movement of the air. An explosion is a rapid expansion of gasses, which causes movement of the air.
Agressive tread, bad alignment
loose belts