A stone dropped from the top of a tower of height 300 m high splashes into the water of a pong near the base of the tower. When is the splash heard at the top ? Given that the speed of sound in air is `340ms^(-1)? (g=9.8ms^(-2)`.

Explanation

`t_(1)` = time taken by the stone to strike the water surface.
`u = 0, a = 9.8 ms^(-2), x = 300 m, t = ?`
`x = ut_(1) + (1)/(2) at_(1)^(2)`
`300 = 0 + (1)/(2) xx 9.8 xx t_(1)^(2)`
`300 = 4.9 t_(1)^(2) or t_(1)^(2) = (300)/(4.9)`
`t_(1) = 7.82 s`
Time taken by sound to travel a distance of 300 m upward
`t_(2) = (x)/(V) = (300)/(340) = 0.88 s`
Total time after which splash is heard
`t = t_(1) + t_(2)`
= 7.82 + 0.88
= 8.70 s