Question

Sam plays on her violin the concert A with frequency 440 Hz. Brian is at a distance of 5.0 m from Sam,

playing on a flute at the same frequency. Sam remains stationary, while Brian is in motion.

(a) If Brian moves according to x (t) = 5+0.45 t2, how much time passes before Sam hears a beat frequency

of 15 beats/s? Do not forget to include the time it takes for sound to travel to Sam.

(b) If Brian moves instead according to x (t) = 5 − 0.45 t2, describe qualitatively and with a graph the

frequency of the sound that Sam hears from Brian’s flute (assume Sam is no longer playing her violin).

Answer 1

In this we have to use doppler effect of sound to solve.Beat frequency is differece of two sound frequencies.