A airplane approaches at an altitude of 10 km flying at 600 km/hr. 1. If the air temperature at that altitude is -50 °C, what is the speed of sound in air there? 2. How does that differ from the speed of sound in air typically at Earth's surface? 3. If the plane will be overhead in 1 minute, when will we hear it coming? You may assume an average speed along the path from the plane to your ear. 4. Jet engines typically emit sound over a wide spectrum of frequencies, with the maximum sound energy at 200 Hz. From this emitted sound, what frequency do you hear initially when it is 1 minute away, and what frequency do ou hear 1 minute after it has passed by? 5. What would you hear, and when would you hear it, if the plane were "hypersonic", traveling three times the speed of sound, or "Mach 3"? That's approximately the fastest military aircraft in routine service today.
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.
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