Question 23: Waves

Question

With what velocity should an observer approach a stationary sound source, so that the apparent frequency of sound should appear double the actual frequency?

Accepted Answer

$$\begin{array}{ll}
	ext {By using } v^{\prime}=v\left[\frac{v-v_0}{v-v_s}ight] \
\Rightarrow \quad 2 v=v\left[\frac{v-v_0}{v-0}ight] \
\Rightarrow \quad v_0=-v
\end{array}$$
Negative sign indicates that observer is moving opposite to the direction of velocity of sound.

Answer

$$v / 2$$

Answer

$$3 v$$

Answer

$$2 v$$

Answer

$$v$$

Waves

With what velocity should an observer approach a stationary sound source, so that the apparent frequency of sound should appear double the actual frequency?

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