Solving Frequency Question Homework: 1.0 kHz Source Moving Towards/Away

[Mr. Goosemahn]

Homework Statement

A source of sound waves of frequency 1.0 kHz is traveling through the air at 0.50 times the speed of sound. (a) Find the frequency of the sound received by a stationary observer if the source moves towards her. (b) Repeat if the source moves away from her instead.

Homework Equations

v=0.5V

F₀₁ = f_s/1-(v_s/v)

F₀₂ = f_s/1+(v_s/v)

The Attempt at a Solution

I tried plugging in the values that are given to me, but I simply don't obtain the correct results. Please help? Thanks in advance.

 

[rl.bhat]

Show your calculations.

 

[Mr. Goosemahn]

F01 = fs/1-(vs/v)

F02 = fs/1+(vs/v)

Using these equations, I plugged in:

1/1+(343/171.5) = 3

1/1-(343/171.5) = -1

I'm not sure if I must do something regarding the 1kHz given to me, but neither of both numbers are valid answers.

 

[rl.bhat]

Fs' = Fs/(1 - Vs/V)
Fs = 1kHz, Vs = 171.5 m/s and V = 343 m/s.
Now try.