Using a spectrum analyzer, we could determine the observed frequency when the car was driving away was 244 Hz and the stationary frequency was 257 Hz. Use this information and the equation to estimate the speed of the car in miles/hour, to 1 decimal place.
Properties of sound
A sound wave is a mechanical wave (or mechanical vibration) that transit through media such as gas (air), liquid (water), and solid (wood).
Quality Of Sound
A sound or a sound wave is defined as the energy produced due to the vibrations of particles in a medium. When any medium produces a disturbance or vibrations, it causes a movement in the air particles which produces sound waves. Molecules in the air vibrate about a certain average position and create compressions and rarefactions. This is called pitch which is defined as the frequency of sound. The frequency is defined as the number of oscillations in pressure per second.
Categories of Sound Wave
People perceive sound in different ways, like a medico student takes sound as vibration produced by objects reaching the human eardrum. A physicist perceives sound as vibration produced by an object, which produces disturbances in nearby air molecules that travel further. Both of them describe it as vibration generated by an object, the difference is one talks about how it is received and other deals with how it travels and propagates across various mediums.
The Doppler effect causes a sound moving towards you to sound higher pitched and a sound moving away from you to sound lower pitched, like observed in listening to the car horn in the video.
The equation for this is f=(cc+v)f0f=(cc+v)f0, where
f is the observed frequency (pitch) of the sound, in Hertz
c is the speed of sound, about 761 miles per hour,
v is the speed of the sound source, in this case the car, in miles per hour
f0 is the frequency of the sound when stationary
Using a spectrum analyzer, we could determine the observed frequency when the car was driving away was 244 Hz and the stationary frequency was 257 Hz.
Use this information and the equation to estimate the speed of the car in miles/hour, to 1 decimal place.
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