(1.2 104)(8.4 10^-9) solve and express your answer in scientific notation

The magnets would be | n s | and | s n|

Gotta have a picture ^^

Sounds propagates through some kind of medium. usually it's air, but it goes just as well through solid objects like walls, windows etc. a soundwave will compress the (air)molecules in front of it, and if this increased density wave hits your ears, you register it as sound. solid objects like walls are a lot denser than air, this means that they will damp a wave, but also carry it easier.