Question

The speed of sound at sea level is normally about 340 m/s. A stationary fire alarm has a frequency of 15,000 Hz. An observer running towards the fire alarm hears a frequency of 15,300 Hz. What is the velocity of the observer?

Answer 1

The velocity of the observer is 6.8 m/s

Step-by-step explanation:

Doppler effect equation is given by the formula:

`f'=(v+v_o)/(v-v_s) f\\\\where\ f'\ is \ the\ observed \ frequency=15300\ Hz,v_o\ is\ the\ velocity\ of\ the\ observer,\\v_s\ is\ the\ velocity\ of \ source=0,v\ is\ the\ velocity\ of\ sound=340\ m/s\ and\ f\ is\ actual\\frequency=15000\ Hz.\\\\substituting:\\\\15300=15000((340+v_o)/(340) )\\\\340+v_o=346.8\\\\v_o=6.8\ m/s`The velocity of the observer is 6.8 m/s