A train station bell gives off a fundamental tone of 470 Hz as the train approaches the station at a speed of 28 m/s.If the speed of sound in air is 349 m/s,what will be the apparent frequency of the bell to an observer riding the train?

Question

Quizplus · Accepted Answer

The Doppler effect formula for frequency of a sound source moving towards a stationary observer is given by:
f' = (v + v_observer) / (v + v_source) * f
where v is the speed of sound in air, v_observer is the speed of the observer, v_source is the speed of the source, and f is the actual frequency of the source.

In this case, the source (the bell) is moving towards the observer (the person riding the train) with a speed of 28 m/s. The speed of sound in air is given as 349 m/s. The actual frequency of the bell is 470 Hz.

Plugging these values into the Doppler effect formula, we get:
f' = (349 + 28) / (349 + 0) * 470
f' = 1.080 * 470
f' = 508 Hz

Therefore, the apparent frequency of the bell to an observer riding the train is 508 Hz.

A Train Station Bell Gives Off a Fundamental Tone of 470