4.(a) A French submarine and an American submarine move towards each other during maneuvers in motionless water in the Northern Atlantic. The French sub moves at speed of 55 km/h and the US sub at 75 km/h. The French sub sends out a sonar signal(sound wave in water) at 1,56 x 103 Hz. Sonar waves travel at 5470 km/h. i) What is the signal’s frequency as detected by the US sub? ii) What frequency is detected by the French sub in the signal reflected back to it by the US sub?
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.
4.(a) A French submarine and an American submarine move towards each other during maneuvers in motionless water in the Northern Atlantic. The French sub moves at speed of 55 km/h and the US sub at 75 km/h. The French sub sends out a sonar signal(sound wave in water) at 1,56 x 103 Hz. Sonar waves travel at 5470 km/h.
i) What is the signal’s frequency as detected by the US sub?
ii) What frequency is detected by the French sub in the signal reflected back to it by the US sub?
(b) Compare red shift with blue shift.
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