Question

A stone is dropped from a height of 7.84 m above water surface. if the splash sound is heard after 4.26 s what is the velocity of sound in the air
(IX class )
(3mark question)

Answer 1

Time taken by stone to fall = sqrt(2H/g)
= sqrt(2 * 7.84/9.8)
= 1.26 seconds

Time taken by sound to travel from water to observer = 4.26 - 1.26
= 3 seconds

Velocty of sound = Displacement / Time
= 7.84 / 3
= 2.6 m/s

Note: In real velocity of sound is much higher.

Answer 2

Answer:

2.6m/s

Explanation:

7.84 / 3 = 2.6 m/s