Does a falling object emit sound from high to low pitches? When watching films or TV shows, it is common that when an object is falling,some sound is emitting from high to low pitch, but in real life, does a falling object emits sound like this? Or it is just a sound effect just for fun?
 A: This sound is real. It originates from vibration of the vanes and other mechanical parts of a falling bomb, excited by the turbulence of the air flow around the falling body.
The change in pitch is owing to the change in the component of the velocity joining the hearer and the falling object: it is this component that determines the Doppler shift of the sound, exactly like the falling pitch of a train horn as the train approaches and passes you. If a body is falling vertically to a point a distance $d$ from the hearer, the sine of the elevation angle when the body is at a height $h$ is $\frac{h}{\sqrt{h^2+d^2}}$. Assuming the bomb has reached terminal velocity (a good approximation for a bomb dropped from WWII bombing heights), the component of its velocity towards the user is proportional to this value. Therefore, the pitch falls with the bomb, because $h$ decreases in this equation.
A: The bombs used in World War used to have a side effect of that noise. They liked it and they amplified it to scare  the people before death and around them.
A: Yes it produces sound because the particle of the substance is in the random motion .When it touches to the ground the force duturbs the particle  and force of attraction of the particle  vibrates  molecules.therefore vibration produces the sounds.sometimes we cannot hear the sound as in the case of sponge because only a sort of sound is produced .therefore sound is produced sometimes it can't be heard....
