A stone is dropped from the top of a tower `500 m` high into a pond of water at the base of the tower. When is the splash heard at the top ? Given, `g = 10 m//s^2` and speed of sound `= 340 m//s`.

Explanation

Here, height through which the stone falls, `h = 500 m`
speed of sound, `v = 340 m//s, g = 10 m//s^2`
If `t` is the time taken by the stone to fall through `h`, then
`h = (1)/(2) g t^2` or `t = sqrt((2 h)/(g))` or `t = sqrt((2 xx 500)/(10)) = 10 s`
Further, if `t'` is the time taken by sound (produced as a result splashing) to travel to the top of the tower,
`t' = (h)/(v) = (500)/(340) = 1.47 s`
Time after which the splash is heard at the top of the tower `= t + t' = 10 s + 1.47 s`
=`11.47 s`.