<span>since sound travels using mechanical waves and needs a material medium to propagate and since mechanical waves spread through vibrations ...and since hard materials have their atoms packed closely....they need to vibrate with a smaller amplitude to pass on the wave....thus sound travels faster in a denser medium than a less dense one.</span>
(3) The frictional force exerted by the floor on the box
Answer: The sound will change due to changes in frequency and the wavelength of the airplane.
Explanation: Let assume that the observer is at a stationary position. The wavelength of the sound from the airplane reduces and the frequency increases as the plane is moving toward the observer. As the airplane passes by, that is, moving away from the observer, the frequency starts to reduce while the wavelength of the sound starts to increase.
The sound that the observer hears will change base on the illustration above.
Yosemite falls has a total height of 73,900 cm it means it heights 739 meters