Please solve question 19 19 A pebble is dropped freely in a well from its top It - Physics - Laws of Motion

Question

Please solve question 19

19 A pebble is dropped freely in a well from its top It takes 20 s
for the pebble to reach the water
surface in the well Taking g = 10 m s–2
and speed of sound = 330 m s–1 find : (i) the
depth of water surface
and (ii) the time when echo is heard after the pebble is dropped

N Dubey · Accepted Answer

Dear student Time taken by the ball to hit the water surface = 20
sec Initial velocity = 0 , acceleration = g = 10m/sÂ²
The height of well = H s = ut + 1/2 a tÂ² H = 0 +1/2 *
10*20*20 H = 2000 meter When pebble strikes the surface then sound
is produced and it comes to observer by travelling the distance of
the well Velocity of sound = 332 m/s , distance = H = 2000 m time
taken by sound to come to observer = t = distance/speed = 2000/332
= 6 02seconds The sound will be heard after 20 + 6 02 = 26 02
seconds Regard