Question

A stone is dropped into a well 44 m deep and the sound of splash is heard after 3.12 sec. Find the speed of sound in air.

Answer 1

Answer:

time taken by stone to reach water is found by

44=1/2 gt^2

44=1/2×10×t^2

44=5t^2

8.8=t^2

t=2.96s

so time taken by sound to come up=3.12 - 2.96

= 0.16s

therefore

speed of sound =44/0.16

=275m/s

Answer 2

Time taken by the stone to reach the water surface can be calculated using the equation of motion s = ut + ½ gt2 Here u = 0, s = 44 m , g = 9.8 m/s2 So t = (2x44/9.8)½ = 2.996 s ≈ 3 s Therefore time taken by sound to travel this distance = 3.12 - 3 = 0.12 s Speed of sound in air = distance covered/Time = 44 m/ (0.12 s) = 366.7 m/s