Physics Homework Help

Question

The predominant frequency of a certain fire truck's siren is 1700 Hz when at rest.

Part A What frequency do you detect if you move with a speed of 24.5 m/s toward the fire truck?

Part B What frequency do you detect if you move with a speed of 24.5 m/s away from the fire truck?

Answer 1

The predominant frequency of a certain fire truck's siren is Hz.

A)

Listener is moving with a speed of m/s.

Speed of the sound is m/s.

Listener is moving towards fire truck which is at rest.

From the Doppler effect, frequency detected by the listener moving toward the source is .

Substitute corresponding values in the formula.

Frequency detected by the listener is  Hz.

Answer 2

The predominant frequency of a certain fire trucks siren is Hz.

B)

Listener is moving with a speed of m/s.

Speed of the sound is m/s.

Listener is moving away from fire truck which is at rest.

From the Doppler effect, frequency detected by the listener moving away from the source  is .

Substitute corresponding values in the formula.

Frequency detected by the listener is Hz.