A sound source moves uniformly on a large circular path with speed u. A stationary observer is so far from the circle that the line of sight may be treated as fixed. What is the ratio of the maximum to the minimum observed frequency?
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Question

A sound source moves uniformly on a large circular path with speed u. A stationary observer is so far from the circle that the line of sight may be treated as fixed. What is the ratio of the maximum to the minimum observed frequency?

Options

G1 Physics · Accepted Answer

The maximum frequency occurs when the source velocity has its maximum component towards the observer: fₘₐₓ = f×v/(v−u). The minimum frequency occurs when the source moves directly away: fₘᵢₙ = f×v/(v+u). Therefore, fₘₐₓ/fₘᵢₙ = (v+u)/(v−u). Correct option: B.