Beats Video Lessons

Video Thumbnail

Concept

Problem: An acoustic burglar alarm consists of a source emitting waves of frequency 28.50 kHz. An intruder is walking at an average speed of 0.9600 m/s directly away from the alarm. Take the speed of sound to be 343.0 m/s.(a) What is the wave length of the source waves?(b) What is the frequency and wavelength for the intruder? The waves are reflected by the intruder and back to the alarm system.(c) What is the frequency and wavelength for the waves reflected from the intruder, as detected at the source?(d) What is the beat frequency between the source waves and the waves reflected from the intruder?

FREE Expert Solution
94% (234 ratings)
Problem Details

An acoustic burglar alarm consists of a source emitting waves of frequency 28.50 kHz. An intruder is walking at an average speed of 0.9600 m/s directly away from the alarm. Take the speed of sound to be 343.0 m/s.

(a) What is the wave length of the source waves?

(b) What is the frequency and wavelength for the intruder? The waves are reflected by the intruder and back to the alarm system.

(c) What is the frequency and wavelength for the waves reflected from the intruder, as detected at the source?

(d) What is the beat frequency between the source waves and the waves reflected from the intruder?

Frequently Asked Questions

What scientific concept do you need to know in order to solve this problem?

Our tutors have indicated that to solve this problem you will need to apply the Beats concept. You can view video lessons to learn Beats. Or if you need more Beats practice, you can also practice Beats practice problems.

How long does this problem take to solve?

Our expert Physics tutor, Juan took 7 minutes and 35 seconds to solve this problem. You can follow their steps in the video explanation above.

What professor is this problem relevant for?

Based on our data, we think this problem is relevant for Professor Nale's class at BU.