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The equation refers to Doppler Effect, which is the change in frequency of a wave in relation to an observer who is moving relative to the wave source.
Yes, I can. The equation corresponds to a source moving towards a stationary observer (fa>f). The source sounds higher in pitch.
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We’re back with another equation puzzle! Do you know what this one refers to? Hint: it has something to do with this month’s theme (check out the pinned post on our profile). 