A whistle of frequency $$500$$ Hz tied to the end of a string of length $$1.2$$ m revolves at $$400$$ $$rev/min$$. A listener standing some distance away in the plane of rotation of whistle hears frequencies in the range (speed$$ of sound $$=$$ $$340$$ $$m/s)

Question

Infinity Learn · Accepted Answer

The linear velocity of Whistle $$vS=r$$ω$$=1.2$$×$$2$$$$π$$$$40060=50$$ $$m/sWhen$$ Whistle approaches the listener, heard frequency will be maximum and when listener recedes away, heard frequency will be minimumSo, $$nmax=n$$ vv−$$vs=500$$ $$340290=586Hznmin=$$ n $$vv+vs=500$$ $$340390=436Hz$$

A whistle of frequency 500 Hz tied to the end of a string of length 1.2 m revolves at 400 rev/min. A listener standing some distance away in the plane of rotation of whistle hears frequencies in the range (speed of sound = 340 m/s)

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