Question

A trumpet emits a sound frequency equivalent to 100Hz. If the person using

the trumpet is moving towards the listener, what would be the perceived

frequency of the listener if the velocity of the sound is 350 m/s and the man

using the trumpet is moving at the rate of 5 m/s?

Answer 1

We can find the frequency observed by the listener from the Doppler Shift formula:

$$f_o=f_s(\dfrac{v}{v-v_s}),$$ $$f_o=100\ Hz\times(\dfrac{350\ \dfrac{m}{s}}{350\ \dfrac{m}{s}-5\ \dfrac{m}{s}})=101.45\ Hz.$$