91Ó°ÊÓ

What sound intensity is \(3.0 \mathrm{~dB}\) louder than a sound of intensity of \(10 \mu \mathrm{W} / \mathrm{cm}^{2}\) ?

An organ pipe is tuned to emit a frequency of \(196.00 \mathrm{~Hz}\). When it and the G string of a violin are sounded together, ten beats are heard in a time of exactly \(8 \mathrm{~s}\). The beats become slower as the violin string is slowly tightened. What was the original frequency of the violin string?

A locomotive moving at \(30.0 \mathrm{~m} / \mathrm{s}\) approaches and passes a person standing beside the track. Its whistle is emitting a note of frequency \(2.00 \mathrm{kHz}\). What frequency will the person hear \((a)\) as the train approaches and (b) as it recedes? The speed of sound is \(340 \mathrm{~m} / \mathrm{s}\).

Two cars are heading straight at each other with the same speed. The horn of one \((f=3.0 \mathrm{kHz})\) is blowing, and is heard to have a frequency of \(3.4 \mathrm{kHz}\) by the people in the other car. Find the speed at which each car is moving if the speed of sound is \(340 \mathrm{~m} / \mathrm{s}\).

To determine the speed of a harmonic oscillator, a beam of sound is sent along the line of the oscillator's motion. The sound, which is emitted at a frequency of \(8000.0 \mathrm{~Hz}\), is reflected straight back by the oscillator to a detector system. The detector observes that the reflected beam varies in frequency between the limits of \(8003.1\) \(\mathrm{Hz}\) and \(7996.9 \mathrm{~Hz}\). What is the maximum speed of the oscillator? Take the speed of sound to be \(340 \mathrm{~m} / \mathrm{s}\).