A person standing on the edge of a well throws a stone vertically upwards with an initial velocity `5ms^(-1)`. The stone gone up, comes down and falls in the well making a sound. If the person hears the sound 3 seconds after throwing the the depth of water (neglect time travel for the sound and take `g=10ms^(-2)`)

Options

A. 1.25 m
B. 21.25 m
C. 30 m
D. 32.5 m

Answer

C

Explanation

`h=-ut+(1)/(2)g t^(2)`