Other Sound Principles

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MCAT Physical › Other Sound Principles

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A guitar player uses beats to tune his instrument by playing two strings. If one vibrates at 550 Hz and the second at 555 Hz, how many beats will he hear per minute?

$300 \textup{\textup{ bpm}}$

$50 \textup{\textup{ bpm}}$

$\frac{1}{12} \textup{\textup{ bpm}}$

$\frac{1}{2} \textup{\textup{ bpm}}$

$5 \textup{\textup{ bpm}}$

Explanation

Two waves will emit a beat with a fequency equal to the difference in frequency of the two waves. In this case the beat frequency is:

$555 - 550=5 \textup{\textup{ Hz}}$ (beats per second)

Convert to beats per minute:

$5 \textup{\textup{ Hz}}\times \frac{60}{1} \frac{seconds}{minutes} = 300 \textup{\textup{ bpm}}$

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