Question

Tina is driving her sports car down US1, traveling 27m/s. She sees her friend Rita up ahead, waiting to cross the street at the next intersection. Tina quickly slams down on the horn. If the horn has a frequency of 400Hz, which of the following is the only possible frequency heard by Rita, as Tina drives away from Rita?

Answer 1

`f_1 = 370.8 Hz`

Step-by-step explanation:

As Tina drives away from Rita

so here we can use the concept of doppler's Effect

`f_1 = f_0((v)/(v+v_s))`

here we know that

`f_0 = 400 Hz`

`v_s = 27 m/s`

`v = 343 m/s`

now we have

`f_1 = f_0((v)/(v + v_s))`

`f_1 = 400((343)/(343 + 27))`

`f_1 = 370.8 Hz`