An airplane with an airspeed of 58km/h lands on a runway where the wind speed is 38km/h. What is the landing speed of the plane if the wind is head-on? Express your answer to two significant figures and include the appropriate unit.

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.

Sound wavelength of visible light waves

Idk