Chapter 6: Problem 15

A person riding on a bus hears the sound from a horn on a car that is stopped. What is different about the sound when the bus is approaching the car compared to when the bus is moving away from the car?

Short Answer

Expert verified

Answer: The Doppler Effect causes the sound of the car horn to have different pitches when the bus is approaching and moving away from the car. When the bus approaches the car, the pitch of the car horn's sound increases due to the compression of sound waves. In contrast, when the bus moves away from the car, the pitch of the sound decreases as the sound waves become stretched.

Step by step solution

Understand Doppler Effect

The Doppler Effect occurs due to the relative motion between the source of the sound (car's horn) and the observer (person on the bus). As the observer moves towards or away from the source, the frequency of the sound wave they hear changes. The change in frequency affects the pitch (or tone) of the sound.

Determine the effect when the bus is approaching

When the bus is moving towards the car, the person on the bus is approaching the source of the sound, causing the sound wave to become compressed. This compression results in an increase in frequency and, consequently, an increase in pitch. So, the sound the person hears will be higher in pitch compared to the actual sound of the horn when the bus is stationary.

Determine the effect when the bus is moving away

When the bus is moving away from the car, the person on the bus is moving farther from the source of the sound, causing the sound wave to become stretched. This stretching results in a decrease in frequency and, consequently, a decrease in pitch. So, the sound the person hears will be lower in pitch compared to the actual sound of the horn when the bus is stationary.

Compare the sounds heard when approaching and moving away

The key difference in the sounds heard by the person on the bus when approaching and moving away from the car lies in the pitch of the sound. As the bus approaches the car, the pitch of the car horn's sound increases, while as the bus moves away from the car, the pitch of the sound decreases. This difference in pitch is due to the Doppler Effect, which is caused by the relative motion between the source of the sound (car's horn) and the observer (person on the bus).

Unlock Step-by-Step Solutions & Ace Your Exams!

Full Textbook Solutions
Get detailed explanations and key concepts
Unlimited Al creation
Al flashcards, explanations, exams and more...
Ads-free access
To over 500 millions flashcards
Money-back guarantee
We refund you if you fail your exam.

Start your free trial

Over 30 million students worldwide already upgrade their learning with Vaia!

Recommended explanations on Physics Textbooks

View all explanations

What do you think about this solution?

We value your feedback to improve our textbook solutions.

A person riding on a bus hears the sound from a horn on a car that is stopped. What is different about the sound when the bus is approaching the car compared to when the bus is moving away from the car?

Short Answer

Step by step solution

Understand Doppler Effect

Determine the effect when the bus is approaching

Determine the effect when the bus is moving away

Compare the sounds heard when approaching and moving away

One App. One Place for Learning.

Most popular questions from this chapter

Recommended explanations on Physics Textbooks

Physics of Motion

Electric Charge Field and Potential

Nuclear Physics

Scientific Method Physics

Fundamentals of Physics

Force

Study anywhere. Anytime. Across all devices.