Answer:
1.4 Hz
Explanation:
[tex]f_{actual}[/tex] = actual frequency emitted from the tuning fork = 269 Hz
[tex]f_{obs}[/tex] = frequency observed
Δf = beat frequency
v = speed of walk = 0.9 m/s
V = speed of sound = 343 m/s
Observed frequency is given as
[tex]f_{obs}= f_{obs}\left ( \frac{V+ v}{V - v} \right )[/tex]
[tex]f_{obs}= (269)\left ( \frac{343 + 0.9}{343 - 0.9} \right )[/tex]
[tex]f_{obs} = 270.4[/tex]
Beat frequency is given as
Δf = [tex]f_{obs} - [tex]f_{actual}[/tex]
Δf = 270.4 - 269
Δf = 1.4 Hz
