Question

A pebble is dropped into a well of depth h . The splash is here after time t .if c is the velocity of sound. Then what will be t

Answer 1

wkt,s=ut=1/2at^2........FROM-EQUATION OF MOTION
From origin to surface of water;
u=0
a=g
s=h
t=?
Then, h=0+1/2gt^2
=>t=(2h/g)^1/2............(I)
From surface of water to our ears;
speed of sound (given)=c
displacement=h
time taken =t1(let)
So velocity of sound=displacement/time taken
i.e; c=h/t1
=>t1=h/c..............(II)
So total time=t+t1
=(2h/g)^1/2 +h/c