Question

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?

a) (a) (4200 Hz); (b) (2800 Hz)
b) (a) (4400 Hz); (b) (2600 Hz)
c) (a) (4600 Hz); (b) (2400 Hz)
d) (a) (4800 Hz); (b) (2200 Hz)

Answer 1

When the jet flies directly toward the stands, the observers receive a frequency of 4200 Hz. When the jet flies directly away from the observers, they receive a frequency of 2800 Hz.

Step-by-step explanation:

When the jet flies directly toward the stands, the frequency observed by the observers is given by the formula:

f_observed = (v_sound + v_jet) / (v_sound) * f_emitted

Plugging in the given values, we get:

f_observed = (342 m/s + 1200 km/h) / (342 m/s) * 3500 Hz = 4200 Hz

When the plane flies directly away from the observers, the frequency observed is given by:

f_observed = (v_sound - v_jet) / (v_sound) * f_emitted

Plugging in the given values, we get:

f_observed = (342 m/s - 1200 km/h) / (342 m/s) * 3500 Hz = 2800 Hz