Question

A stone is dropped from the roof of a building and takes 5 seconds to reach the ground. The sound of striking is heard after 5.4 seconds of the stone being dropped. The velocity of sound is?

Answer 1

h=ut+ 1/2at^2

u=0

h= 1/2 x g x (5)^2 = 10/20 x 5 x 5 = 125 m

Now time taken by sound to go up is

5.4−5=0.4 sec

Distance = 125 m , t=0.4 sec

Velocity of sound =

125/0.4

​=312.5 m/s

Hope it helps!