contestada

(a) At an air show a jet flies directly toward the stands at a speed of 1200 km/h, emitting a frequency of 3500 Hz, on a day when the speed of sound is 342 m/s. What frequency is received by the observers? (b) What frequency do they receive as the plane flies directly away from them?

Respuesta :

Answer:

a) 1.4 x 10⁵ Hz

b) 1.8 x 10³ Hz

Explanation:

a)

[tex]V_{s}[/tex] = speed of sound = 342 m/s

[tex]V_{j}[/tex] = speed of jet = 1200 km/h = 333.33 m/s

[tex]f_{a}[/tex] = actual frequency = 3500 Hz

[tex]f_{obs}[/tex] = observed frequency

Observed frequency is given as

[tex]f_{obs} = \frac{f_{s}V_{s}}{V_{s} - V_{f}}[/tex]

[tex]f_{obs} = \frac{(3500)(342)}{342 - 333.33}\\[/tex]

[tex]f_{obs}[/tex] = 1.4 x 10⁵ Hz

b)

[tex]V_{s}[/tex] = speed of sound = 342 m/s

[tex]V_{j}[/tex] = speed of jet = 1200 km/h = 333.33 m/s

[tex]f_{a}[/tex] = actual frequency = 3500 Hz

[tex]f_{obs}[/tex] = observed frequency

Observed frequency is given as

[tex]f_{obs} = \frac{f_{s}V_{s}}{V_{s} + V_{f}}[/tex]

[tex]f_{obs} = \frac{(3500)(342)}{342 + 333.33}\\[/tex]

[tex]f_{obs}[/tex] = 1.8 x 10³ Hz