Question

a stone is dropped into a well 44.1m deep. after how much time the sound will be heard if the velocity of sound is330m/s.

Answer 1

Depth of the wall = 44.1 m
​Time of hearing sound = 3.13 s
Time taken by the stone to reach the bottom of the well can be calculated by the relation :
s = ut + 1/2 at2
Since, u = 0 m/s and a = 9.8 ms-2
t 2 = 2s/a
we get, t = 3 sec
Since, the total time for the stone to reach the well and again to travel to same distance due to reflection of sound is 3.13 sec as the stone took 3 sec to reach the bottom of the well.
Therefore, the sound will only take to 0.13 sec to reach the observer who listened the sound.
Hence, speed of sound = distancetravelledbythesoundtimetakenbythesoundtoreactheobserver
= 441m013s33923ms1