A
sonic boom can be generated by any
sound-
emitting object capable of travelling at or near the
speed of sound. Note that
air resistance produces sufficient
noise to
generate a
sonic boom.
Consider a car travelling towards an observer at approximately the speed of sound (around 1000 km/h or 600 mph),
blaring its horn. Since the sound waves produced by the car horn can't travel any faster
than the car itself, the noise generated by the blaring horn essentially stacks up. All the noise generated by the car horn will hit the observer at once.
This is fundamentally similar to how a boat creates a bow wave (wake) -- waves generated by a boats motion through water stack in very much the same way, creating a v-shaped wave trailing behind the boat.
Guile, a playable video game character first seen in Street Fighter 2 would yell 'Sonic boom!' when releasing a forward-moving projectile. To perform a sonic boom, hold away from your opponent on the joystick for two seconds, then simultaneously press the joystick towards your opponent and a punch button. Different punch buttons generate projectiles of different velocities. Guile's other trademark technique is a Flash Kick.
Sources:
- How Stuff Works:
- http://www.howstuffworks.com