Question

You hear the engine roaring on a race car at the starting line. Predict the changes in the sound as the race starts and the car approaches the camera. A) The sound of the engine will get louder and the pitch lower. Eliminate B) The sound of the engine will get louder and the pitch higher. C) The sound is determined by the car and it will not change in any way. D) The sound of the engine will get louder but the pitch will not change.

Answer 1

Answer: The correct option is B.

Explanation:

Doppler effect is the phenomenon in which there is an apparent change in the frequency when there is relative motion between source and listener.

When the source and the listener are approaching each other then the frequency increases. The loudness depends on the amplitude. The energy of the wave is directly proportional to the square of the amplitude.

In the given problem, the engine is roaring on a race car at the starting line. There is change in the sound as the race starts and the car approaches the camera.

Pitch depends on the frequency.

Therefore, the sound of the wave will get louder and the pitch will get higher.

Answer 2

B. The sound of the engine will get louder and the pitch higher.