Question 215: Waves

Question

A whistle producing sound waves of frequencies $$9500$$ $$Hz$$ and above is approaching a stationary person with speed $$v$$ $$m{s^{ - 1}}.$$ The velocity of sound in air is $$300\,m{s^{ - 1}}.$$ If the person can hear frequencies upto a maximum of $$10,000$$ $$HZ,$$ the maximum value of $$v$$ upto which he can hear whistle is

Accepted Answer

$$v' = v\left[ {{v \over {v - {v_s}}}} ight] \Rightarrow 10000$$
$$ = 9500\left[ {{{300} \over {300 - v}}} ight]$$
$$ \Rightarrow 300 - v = 300 	imes 0.95 \Rightarrow v$$
$$ = 300 - 285 = 15\,m{s^{ - 1}}$$

Answer

$$15\sqrt 2 \,\,m{s^{ - 1}}$$

Answer

$${{15} \over {\sqrt 2 }}\,m{s^{ - 1}}$$

Answer

$$15\,\,m{s^{ - 1}}$$

Answer

$$30\,\,m{s^{ - 1}}$$

Waves

A whistle producing sound waves of frequencies $9500 Hz and above is approaching a stationary person with speed v m{s^{ - 1}}. The velocity of sound in air is 300\,m{s^{ - 1}}. If the person can hear frequencies upto a maximum of 10,000 HZ, the maximum value of v$ upto which he can hear whistle is

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