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Question
A man is standing between two vertical walls 680 m apart. He claps his hands and hears two distinct echoes after 0.9 seconds and 1.1 seconds respectively. What is the speed of sound in the air?
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Solution
Given data is
d = 680 m
t1 = 0.9 s
t2 = 1.1 s
v = ?
Velocity = `"Distance travelled by sound"/"Time taken"`
V= `(2"d")/t`
d1 = `("vt"_1)/2` & d2 = `("vt"_2)/2`
d = `"v"/2` (t1 + t2)
V = `(2"d")/(("t"_1 + "t"_2))`
= `(2xx680)/((0.9 + 1.1))`
= `(2xx680)/2`
V= 680 ms-1
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