Question 531: Waves

Question

A man stands between two parallel cliffs (not in middle). When he claps his hands, he hears two echoes one after is and the other after $$2 \mathrm{~s}$$. If the velocity of sound in air is $$330 \mathrm{~m} / \mathrm{s}$$, the width of the cliff is

Accepted Answer

Let $$x=$$ width of the cliff.
$$y=$$ distance of man from one cliff, then $$(x-y)=$$ distance of man from second cliff.
Hence, $$2 y=1 	imes 330$$
and $$2(x-y)=2 	imes 330$$
Hence, $$2 x=2 	imes 330+330$$
$$	herefore \quad x=\frac{990}{2}=495 \mathrm{~m}$$

Answer

330 m

Answer

495 m

Answer

660 m

Answer

990 m

Waves

A man stands between two parallel cliffs (not in middle). When he claps his hands, he hears two echoes one after is and the other after $2 \mathrm{~s}. If the velocity of sound in air is 330 \mathrm{~m} / \mathrm{s}$, the width of the cliff is

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